# Backup generator for a theater



## sotonfan (Jan 27, 2021)

My boss has asked me to develop a proposal for installing one or more backup generators for our theater. We have a 1700-seat auditorium on one side, and a 350-person ballroom on the other side. Twice in the past few years we have had a major power outage on our block when there was a wedding on one side and a show on the other at the same time. It was a real mess, for patrons and also for promoters and bands. (Loading out a full rock band in the dark is something I hope never to do again, but it was less painful than moving a wedding across town with an hour to spare.)

I talked to the power company, who calculated our peak load in the heaviest time of the year was 312KW. 

Does anyone have experience with this process? Is my boss asking for something impossible? Or is this a reasonable idea? We have room on our roof for generators - especially if they can run on natural gas. There's very little footprint on the ground for anything. 

Thanks for any suggestions on how to start tackling this one. Pretty sure we can't start until COVID is behind us, since I'm sure it will require some fund-raising...
Andrew


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## dmx (Jan 27, 2021)

Andrew,
The cost for a 250Kw generator and electrical interface will likely price you between 65 - 125K depending on your location and features requested. Perhaps a more realistic option would be to hire an electrician to install a generator tie-in, where you would rent a generator in case of emergency. This may not be feasible during non-standard business hours if you are in the event industry.
Another option to consider is load shedding. Even in our military installs, rarely are our buildings wired for 100% emergency backup loads. Essential components (lighting/ critical equipment) are always included but many rooms have 1-2 backup circuits at most. I think your best bet would be to consult with a local firm and start gathering quotes, perhaps for multiple configuration options.
--Matt

(For the record, one of our installs includes a 1.3MW generator paired with a 750Kw unit used for mission-essential loads. It is really more of a question of budget than size.)


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## RonHebbard (Jan 27, 2021)

sotonfan said:


> My boss has asked me to develop a proposal for installing one or more backup generators for our theater. We have a 1700-seat auditorium on one side, and a 350-person ballroom on the other side. Twice in the past few years we have had a major power outage on our block when there was a wedding on one side and a show on the other at the same time. It was a real mess, for patrons and also for promoters and bands. (Loading out a full rock band in the dark is something I hope never to do again, but it was less painful than moving a wedding across town with an hour to spare.)
> 
> I talked to the power company, who calculated our peak load in the heaviest time of the year was 312KW.
> 
> ...


*@sotonfan* Having space and natural gas available on your roof is only part of the puzzle: 
Will your roof support the physical point load of a V12 generator?
Several theatres within a 50 mile radius of my abode have backup generators. Keeping them warm and ready to rock during Canadian winters is another expense and consideration. 
Toodleoo! 
Ron Hebbard


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## DrewE (Jan 27, 2021)

Are you looking to be able to continue the show or event uninterrupted when the utility power unexpectedly goes out, or simply to resume it after a hopefully brief interruption? Or, perhaps, to not necessarily have it continue, but simply have greater comfort and safety for getting people on their way and cleaning up afterwards?

The first rather obviously requires, in addition to the generator, a not insubstantial UPS system, and all the expense and space and maintenance involved in that. The second scenario may involve more than a brief interruption if there are many computerized show systems that have to be reset, reloaded, and advanced to an appropriate restarting point. Ideally such systems would be on their own UPS or other backup power source to avoid such a delay, but I suspect enforcing that especially with outside groups using the facility would prove impracticable.

(How well acoustically isolated is the roof from the venue interior?)


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## sk8rsdad (Jan 27, 2021)

My $.02 is while it is possible to install and maintain a backup generator, it's not very practical for a theatre, leastways not for the purpose of going on with the show. If the facility is a designated emergency center that might be a different matter. My venue has battery backup on some critical systems like booth consoles and emergency lighting. It's enough to ride out momentary interruptions or evacuate the theatre for prolonged outages.


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## RonHebbard (Jan 27, 2021)

DrewE said:


> Are you looking to be able to continue the show or event uninterrupted when the utility power unexpectedly goes out, or simply to resume it after a hopefully brief interruption? Or, perhaps, to not necessarily have it continue, but simply have greater comfort and safety for getting people on their way and cleaning up afterwards?
> 
> The first rather obviously requires, in addition to the generator, a not insubstantial UPS system, and all the expense and space and maintenance involved in that. The second scenario may involve more than a brief interruption if there are many computerized show systems that have to be reset, reloaded, and advanced to an appropriate restarting point. Ideally such systems would be on their own UPS or other backup power source to avoid such a delay, but I suspect enforcing that especially with outside groups using the facility would prove impracticable.
> 
> (How well acoustically isolated is the roof from the venue interior?)


If you want to see "a not insubstantial UPS system, and all the expense and space and maintenance involved in that", visit any of Las Vegas's serious casino's. If patrons are gambling, they want zero distractions / interruptions and have literally tons of weight and money invested in batteries to power their UPS's. 
*@derekleffew* Care to comment?
Toodleoo! 
Ron Hebbard


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## RonHebbard (Jan 27, 2021)

sk8rsdad said:


> My $.02 is while it is possible to install and maintain a backup generator, it's not very practical for a theatre, leastways not for the purpose of going on with the show. If the facility is a designated emergency center that might be a different matter. My venue has battery backup on some critical systems like booth consoles and emergency lighting. It's enough to ride out momentary interruptions or evacuate the theatre for prolonged outages.


Having your Clear Com / production intercom and God mic' system on a UPS is also money well spent for inter-department communication and crowd instruction / control. 
Toodleoo! 
Ron Hebbard


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## MNicolai (Jan 27, 2021)

We do a lot of projects with standby and/or life safety generators. In most cases, 100% transfer of the load is not the target goal unless it's a data server farm, EOC, or call center, in which case there is N+1 redundancy sharing the total load across multiple generators with one spare ready to go if one of the others has a fault. Most projects end up having load shedding to a generator or sometimes a UPS battery farm with inverters for the purposes of keeping only essential systems and life safety lighting online. Depending on where the venue is based, that may or may not involve major mechanical systems -- often only data closets will remain temperature controlled and other mechanical systems will be shut off.

If you go through the trouble of installing a generator only to have to put it on the roof, then you are going to have sound and vibration problems that will make it difficult to keep your event going uninterrupted anyway, in addition to the structural considerations associated with that. Other considerations for a rooftop installation is that you often need to provide screening so it's not an eyesore if it's visible from the street, and having it on the roof means the noise from it will travel a _long_ distance. Which will make you the subject of noise complaints when you cycle it monthly to keep it in good working order.

Impossible? Not at all. Cheap? Also not at all. 350-400kW plus redoing your switchgear to accommodate an ATS as well as any life safety implications that may be involved is not a small undertaking. Possible, but with a price tag.

Segmenting out critical systems and only transferring those to a generator is more digestible -- but even that is no small undertaking because you may still require a sizable overhaul of how your panelboard distribution to branch circuits are configured. As with all things though, anything is possible if you draw your idea on the back of a big enough check.


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## derekleffew (Jan 27, 2021)

RonHebbard said:


> ... patrons are gambling, they want zero distractions / interruptions and have literally tons of weight andat", visit any of Las Vegas's serious casino's. money invested in batteries to power their UPS's.
> *@derekleffew* Care to comment?


Okay, since I've been dragged unwillingly into this, a story...

Upon opening, a major resort proudly bragged of its ten or twelve, can't remember, Caterpillar back-up diesel generators. A few years later, the entire property went dark and closed for THREE days. While building a second tower, workers had some how cut through the wrong feeder.



__





Bellagio blackout creates surreal scene

Rather than the usual sound of casino games, silence greeted thousands of Bellagio guests Sunday, as the 3,005-room resort was plunged into darkness because of a massive power failure.



lasvegassun.com





As for UPSs, what I've seen is no different than any other large IT services install.


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## SteveB (Jan 27, 2021)

At the OP, you want to be contacting an electrical engineer who can ascertain what needs to be in backup, then design an appropriate system that’ll meet your need as well as local code. You cannot take this on yourself, too many legal issues involved.


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## Ben Stiegler (Jan 27, 2021)

MNicolai said:


> We do a lot of projects with standby and/or life safety generators. In most cases, 100% transfer of the load is not the target goal unless it's a data server farm, EOC, or call center, in which case there is N+1 redundancy sharing the total load across multiple generators with one spare ready to go if one of the others has a fault. Most projects end up having load shedding to a generator or sometimes a UPS battery farm with inverters for the purposes of keeping only essential systems and life safety lighting online. Depending on where the venue is based, that may or may not involve major mechanical systems -- often only data closets will remain temperature controlled and other mechanical systems will be shut off.
> 
> If you go through the trouble of installing a generator only to have to put it on the roof, then you are going to have sound and vibration problems that will make it difficult to keep your event going uninterrupted anyway, in addition to the structural considerations associated with that. Other considerations for a rooftop installation is that you often need to provide screening so it's not an eyesore if it's visible from the street, and having it on the roof means the noise from it will travel a _long_ distance. Which will make you the subject of noise complaints when you cycle it monthly to keep it in good working order.
> 
> ...


That last bit is poetry, Mike!


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## rphilip (Jan 27, 2021)

MNicolai said:


> ... when you cycle it monthly to keep it in good working order.


I want to emphasize this point. 

I work on a university campus and several buildings have backup generators of various sizes. The one for the IT building get tested, with load weekly and has never failed when needed (but it did get very close one). In the event of a power failure the machine room rides over on UPS and the rest of building is back online in <10s + any reboot time. The rest that might only get started every few months seem to invariably take a few hours to get going. I very highly recomend you make sure that any generator gets tested under load regularly (no less than monthly and weekly isn't bad) and any problems are followed up on promptly.


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## FMEng (Jan 27, 2021)

Having dealt with generators from 7 kVA propane to 400 kVA diesel, for broadcast studios and transmitter sites, I concur with everything Mike N and Steve B said. The goal should not be running everything. The goal should be running the barest essentials. Otherwise the size of the generator, and the cost of fuel and maintenance just sky rocket. For example, if the peak load is 350 kVA, you'll need a much larger generator to handle motor starting of HVAC systems. Start the list of what's essential, and what's not, then get an electrical engineer involved. UPS for anything beyond booth equipment and announcement PA would be a waste of money.


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## RonHebbard (Jan 28, 2021)

rphilip said:


> I want to emphasize this point.
> 
> I work on a university campus and several buildings have backup generators of various sizes. The one for the IT building gets tested, with load weekly and has never failed when needed (but it did get very close once). In the event of a power failure the machine room rides over on UPS and the rest of building is back online in <10s + any reboot time. The rest that might only get started every few months seem to invariably take a few hours to get going. I very highly recommend you make sure that any generator gets tested under load regularly (no less than monthly and weekly isn't bad) and any problems are followed up on promptly.


In my area, hospital generators are typically ran under load weekly for ~one hour. 
Within 2020 I was hospitalized in a wing I'd helped build in 1969 during my apprenticeship. When I heard the hospital wide warning announcement, followed by the roar of the V12 diesel several stories above my bed, followed by the barely perceptible blink as the Robonic (Brand) transfer switch threw, I knew EXACTLY where I was. 
Toodleoo! 
Ron Hebbard


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## FMEng (Jan 28, 2021)

Diesel generators really need to be exercised at least monthly, or they will act up when needed. Most of the clocks can only do it weekly. You'd be surprised at how much run time is accrued just by exercising the beasts. They also "wet stack" when run without load, so they need a run with a good load periodically, to cook the crud out of the exhaust system.

I'll never forget the year we moved into new studios, with a brand new, 125 kVA, Caterpillar diesel. About a month after we moved in, we had a 3 hour power outage, right in the middle of "drive time." At that point, the generator had been load tested and exercised some 20 hours. Yet, when duty called, the alternator failed causing the generator to produce no output. The result was the longest off-air period in my entire career. Naturally, once the mechanic arrived, it worked fine. After several service trips, they found an intermittent rectifier module inside the alternator.


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## macsound (Jan 28, 2021)

RonHebbard said:


> In my area, hospital generators are typically ran under load weekly for ~one hour.
> Within 2020 I was hospitalized in a wing I'd helped build in 1969 during my apprenticeship. When I heard the hospital wide warning announcement, followed by the roar of the V12 diesel several stories above my bed, followed by the barely perceptible blink as the Robonic (Brand) transfer switch threw, I knew EXACTLY where I was.
> Toodleoo!
> Ron Hebbard


I'm happy to hear there were some good memories and moments of internal fuzziness associated with your hospitalization. It's always nice to have a positive experience distract you while you're on the mend.
As always, happy you're still with us sir.


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## Ancient Engineer (Jan 28, 2021)

I have a bit of experience and would agree will all of the above. If you really need 100% load transfer you are looking at a substantial ground footprint. We had a ginormous (possibly larger) Liebert UPS that would take the load for exactly 20 minutes.

The generator (750kW) took less than a minute to fire and could be 100% loaded in about 12 minutes. The electronic changeover in the UPS was magnificent to observe as well as the raft of STACO automatic regulators doing their thing...

The footprint for the generator building was about 75' x 150' and housed the UPS batteries (lead-acid) and ventilation. The 35K gallon fuel tank was under the floor. The "hotel" load for the place was around 125kW, but the full load in August with tons of A/C starting all at once was about 470kW.

But at the outlet, the blip was under 4% RMS going in any direction. (mains to ups, ups to gen, gen to mains)

Pretty awesome.


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## sotonfan (Jan 29, 2021)

Thanks much to everyone for your replies. This is exactly the kind of "you get what you pay for" kind of advice I was hoping for! I shall present my boss with some options and see what direction I'm supposed to go. 

I'm not so concerned about uninterrupted service. My main task was to come up with an alternative power source when we have a 24-hour blackout on the morning of a major show. I don't know what's up with power in this town, but there's another major outage this morning, and it's not even snowing. 2,000 customers in the dark, and the only place still running is the hospital which has.... a generator.


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## TimMc (Jan 29, 2021)

sotonfan said:


> Thanks much to everyone for your replies. This is exactly the kind of "you get what you pay for" kind of advice I was hoping for! I shall present my boss with some options and see what direction I'm supposed to go.
> 
> I'm not so concerned about uninterrupted service. My main task was to come up with an alternative power source when we have a 24-hour blackout on the morning of a major show. I don't know what's up with power in this town, but there's another major outage this morning, and it's not even snowing. 2,000 customers in the dark, and the only place still running is the hospital which has.... a generator.



The cost/benefit needs to be calculated for having enough generating capacity to put on a show, as that presumes customer-facing things will work: restrooms, concessions, bar, merch, valet parking, climate control and that all auditorium/stage house things work, too. IOW I'm guessing capacity at 100% of load, plus some overhead. How much will this cost? How much will the *facility* loose if the show does not go on? Is the facility the sole or primary promoter for outside shows?

If the whole city is in the dark (except for the hospital), will people come to a show? No shower, no dinner...

Now... I'm not an EE. I don't know what stuff like this costs these days... but I think you're looking at between $250k-$500k. That might just be a down payment... but you can do a lot of work inside your theater or facility for that kind of coin and have it pay back every time the building is used.


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## Jay Ashworth (Jan 29, 2021)

Ancient Engineer said:


> I have a bit of experience and would agree will all of the above. If you really need 100% load transfer you are looking at a substantial ground footprint. We had a ginormous (possibly larger) Liebert UPS that would take the load for exactly 20 minutes.
> 
> The generator (750kW) took less than a minute to fire and could be 100% loaded in about 12 minutes. The electronic changeover in the UPS was magnificent to observe as well as the raft of STACO automatic regulators doing their thing...
> 
> ...


In an install that big, did you not have some staging in the HVAC controllers to avoid *all* the motors dead-starting simultaneously?


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## Jay Ashworth (Jan 29, 2021)

sotonfan said:


> Thanks much to everyone for your replies. This is exactly the kind of "you get what you pay for" kind of advice I was hoping for! I shall present my boss with some options and see what direction I'm supposed to go.
> 
> I'm not so concerned about uninterrupted service. My main task was to come up with an alternative power source when we have a 24-hour blackout on the morning of a major show. I don't know what's up with power in this town, but there's another major outage this morning, and it's not even snowing. 2,000 customers in the dark, and the only place still running is the hospital which has.... a generator.


Ok, then you're looking at a larger problem, generally termed co-generation; that keyword will take you down a half-million dollar plus rabbit hole...


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## FMEng (Jan 30, 2021)

Jay Ashworth said:


> Ok, then you're looking at a larger problem, generally termed co-generation; that keyword will take you down a half-million dollar plus rabbit hole...


Please explain. Doesn't it all depend on what the building uses for a heat source? If it's natural gas or heat pump, then the power requirements are much less.


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## Ancient Engineer (Feb 1, 2021)

Jay, I wish it was true, but no they were all "free". We were operational testing late one August and I was looking at the fuel racks on the diesel when the HVAC hit and the govenor rolled out to about 95% (from ~20%) and that old FM Diesel barked once and rolled a tower of black smoke a mile high. But, between the STACOs sounding like oven timers and the quick ramp up. nothing was electrically grumpy.

I suspect that by now staging is in place, but back in 1989, not so much.


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## macsound (Feb 1, 2021)

Something I recall in a local hospital are the color of the wall plugs.
If my memory serves me there are 3 colors
1. White (regular power)
2. Blue (fails over to generator power with delay)
3. Red (always powered through UPS then generator without delay)

It was explained to me when there's a patient who's on some equipment that can't be interrupted for any reason, it goes in the red plug, but almost everything else goes in the white plug because many of the standard issue hospital thingies (heart rate, blood oxygen, IV pump) have a battery in them anyway because they need to work in ambulances and while walking down hallways and the side effect is a power outage isn't a big deal.

Could an intermediary idea for your backup system have these types of plugs added and you could determine the dozen or two or three LED theatrical fixtures that would be included in the failover to generator system which would all be fresh wire pulls and leave the existing infrastructure the same?


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## Jay Ashworth (Feb 1, 2021)

macsound said:


> Something I recall in a local hospital are the color of the wall plugs.
> If my memory serves me there are 3 colors
> 1. White (regular power)
> 2. Blue (fails over to generator power with delay)
> ...


Those might have been plate colors; most *receptacle* colors I've seen are white or orange (for isolated ground).

You don't really want receptacles molded in dark colors; too little contrast between the body and the holes makes it hard to aim the plug.


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## FMEng (Feb 1, 2021)

We did outlet color coding in a studio build. The plans included blue receptacles until the electrical sub discovered they are extremely expensive. We wound up using ivory for normal power, orange for generator, and gray for UPS. The contractor was very happy when he found I was flexible on colors.


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## Jay Ashworth (Feb 1, 2021)

Using Orange for non-IG receptacles doesn't violate NEC? I thought that was a dedicated color


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## RonHebbard (Feb 1, 2021)

Jay Ashworth said:


> Those might have been plate colors; most *receptacle* colors I've seen are white or orange (for isolated ground).
> 
> You don't really want receptacles molded in dark colors; too little contrast between the body and the holes makes it hard to aim the plug.


 *@Jay Ashworth* I believe I've seen duplex's colored as described and had little to no trouble discerning orientation: 
- It's rarely THAT dark in a hospital. 
- Good 'Hospital Grade' contractors (The contractors / installers NOT to be confused with Hospital Grade receptacles) normally orient ALL duplex receptacles in the building (or a floor or wing) to contractor / site LX foreman decrees, for example: 
- All vertical receptacles (Duplexes or singles) are to be installed 'Ground up' OR 'Ground down' per the specific contract / Electrical PENG / Company Super intendent / Existing standards all ready installed in older portions of the project. 

- All horizontal receptacles (Duplexes or singles) are to be installed 'Ground left' / 'Ground right' / 'Ground towards the door' / 'Ground towards the windows' / Yada, yada, you've caught the concept. 
Toodleoo! 
Ron Hebbard


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## RonHebbard (Feb 2, 2021)

Jay Ashworth said:


> Using Orange for non-IG receptacles doesn't violate NEC? I thought that was a dedicated color


I've also seen Brown (and possibly Black) isolated ground receptacles with a tiny Green dot near the ground to indicate they were iso grounds. The installation was Madam Tussauds in the top 2 floors of a 3 story building in the heart of the Vegas strip. The receptacles were specified for installation in two specific locations in a wall scheduled to be sprayed flat / matte BLACK in a room where the ceiling / walls / everything except the displays were to be matte black / capable of COMPLETE black outs for a few seconds per automated performance. 
Toodleoo! 
Ron Hebbardd


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## Jay Ashworth (Feb 2, 2021)

RonHebbard said:


> I've also seen Brown (and possibly Black) isolated ground receptacles with a tiny Green dot near the ground to indicate they were iso grounds. The installation was Madam Tussauds in the top 2 floors of a 3 story building in the heart of the Vegas strip. The receptacles were specified for installation in two specific locations in a wall scheduled to be sprayed flat / matte BLACK in a room where the ceiling / walls / everything except the displays were to be matte black / capable of COMPLETE black outs for a few seconds per automated performance.
> Toodleoo!
> Ron Hebbardd


I thought that the green dot meant hospital-grade, not isolated ground. Am I wrong?

Fair Point, though, on the illumination levels .


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## RonHebbard (Feb 2, 2021)

Jay Ashworth said:


> I thought that the green dot meant hospital-grade, not isolated ground. Am I wrong?
> 
> Fair Point, though, on the illumination levels .


In my IBEW days / years, I believe I installed "Hospital Grade" receptacles in at least 7 colors: 
- Black
- Brown
- Red
- Blue 
- Grey
- Ivory 
- Orange
- There may have been Yellow as well.

*At Jay*; I MAY be wrong but I believe many / most of the colors were available iso or non, duplexes or singles. 
Hubbell also used to market a brown duplex with one half 15 amp parallel blade, the other half 15 amp twist; it may have been rated at 20 amps on your side of Donnie's walls or it may not have been approved on your side: Up here north of the walls, our standard utility circuits are breakered / wired / rated for 15 amps .

I don't recall if the parallel / twist duplex was available in an iso ground version. 
Toodleoo! 
Ron Hebbard


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## DrewE (Feb 2, 2021)

The required marking for isolated ground receptacles is apparently an orange triangle. The rest of the installation presumably can be any color that suits one's fancy, one's needs, one's décor, etc.


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## tjrobb (Feb 2, 2021)

DrewE said:


> The required marking for isolated ground receptacles is apparently an orange triangle. The rest of the installation presumably can be any color that suits one's fancy, one's needs, one's décor, etc.



Correct. Green dot for Hospital Grade. Yellow often indicates corrosion-resistant (usually higher current gear) and orange is often IG. Blue is common for integral surge suppression, red for emergency (or the cover plate for a shutdown switch). While colors are not required, those marks are.


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## David Ashton (Feb 3, 2021)

If you are running mainly dimmers and switch-mode power supplied gear you will need to increase the rating of your generator by 25% to allow for the awful power factor which a mains supply can cope with but a generator will really struggle with, the more balanced load gear you load it with the better.


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## Ben Stiegler (Feb 5, 2021)

sotonfan said:


> Thanks much to everyone for your replies. This is exactly the kind of "you get what you pay for" kind of advice I was hoping for! I shall present my boss with some options and see what direction I'm supposed to go.
> 
> I'm not so concerned about uninterrupted service. My main task was to come up with an alternative power source when we have a 24-hour blackout on the morning of a major show. I don't know what's up with power in this town, but there's another major outage this morning, and it's not even snowing. 2,000 customers in the dark, and the only place still running is the hospital which has.... a generator.


Where are you (more specifically than "usa")?


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## themuzicman (Feb 8, 2021)

sotonfan said:


> My main task was to come up with an alternative power source when we have a 24-hour blackout on the morning of a major show. I don't know what's up with power in this town, but there's another major outage this morning, and it's not even snowing. 2,000 customers in the dark, and the only place still running is the hospital which has.... a generator.



A little late to the party on this one, but if it's just a 24 hour blackout and not some instantaneous mid-show event here's an idea from some international venues I've played that ensure compatability with American tours on 120V power - if it's major show you don't need to own the generators, install pass-thru camlock service between the parking lot and the back wall of the venue. Power goes out, call up the local entertainment generator service or have then on retainer during gigs, get them to plug in and re-route the shows feeder. Then you're only worrying about finding backup solutions for the facility proper.


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## RonHebbard (Feb 8, 2021)

themuzicman said:


> A little late to the party on this one, but if it's just a 24 hour blackout and not some instantaneous mid-show event here's an idea from some international venues I've played that ensure compatability with American tours on 120V power - if it's major show you don't need to own the generators, install pass-thru camlock service between the parking lot and the back wall of the venue. Power goes out, call up the local entertainment generator service or have then on retainer during gigs, get them to plug in and re-route the shows feeder. Then you're only worrying about finding backup solutions for the facility proper.


*Facetiously*: Up here north of the walls we're CONSTANTLY being bombarded by advertisements for Generac. Maybe they've got something petite, pretty, and propane powered to tuck away quietly out of sight. 
I did warn you I was being facetious. 
Toodleoo! 
Ron Hebbard


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## Ancient Engineer (Feb 8, 2021)

RonHebbard said:


> petite, pretty, and propane powered



These are the criteria for most of my relationships...


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## TimMc (Feb 8, 2021)

Ancient Engineer said:


> These are the criteria for most of my relationships...


Lady Propane (Hank Hill reference)? I gotta upgrade from steam...


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## FMEng (Feb 8, 2021)

We have a saying in the broadcast world, "Friends don't let friends buy Generac." I prefer Kohler, Caterpillar, or Cummins, and have had positive experiences with all three. Propane is fine for small sizes, but large engines have trouble with a tank vaporizing fuel fast enough without heating apparatus. Natural gas is an alternative to diesel, especially where post earthquake operation isn't a concern. The nice thing about NG is no storage needed.


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## tjrobb (Feb 9, 2021)

FMEng said:


> We have a saying in the broadcast world, "Friends don't let friends buy Generac." I prefer Kohler, Caterpillar, or Cummins, and have had positive experiences with all three. Propane is fine for small sizes, but large engines have trouble with a tank vaporizing fuel fast enough without heating apparatus. Natural gas is an alternative to diesel, especially where post earthquake operation isn't a concern. The nice thing about NG is no storage needed.



I believe that code doesn't allow spark-ignited engines in most cases, if powering life safety equipment. Think it's to do with the complexity.


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## Jay Ashworth (Feb 9, 2021)

tjrobb said:


> I believe that code doesn't allow spark-ignited engines in most cases, if powering life safety equipment. Think it's to do with the complexity.


That would be sensible, but diesel are the only ones which aren't, I think, LP, CNG, etc are all just gas engines with different injection (and gas-tight plumbing), right?


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## tjrobb (Feb 10, 2021)

Jay Ashworth said:


> That would be sensible, but diesel are the only ones which aren't, I think, LP, CNG, etc are all just gas engines with different injection (and gas-tight plumbing), right?



I believe so. 
And yes, it seems like gas pipelines are hardly ever damaged by storms. However, with the derecho last September we had trees falling over and pulling all sorts of utilities out of the ground. (Aside: the damage to the aboveground telephone lines was so bad the owner has opted to abandon the entire plant in lieu of fiber).


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## FMEng (Feb 10, 2021)

tjrobb said:


> I believe that code doesn't allow spark-ignited engines in most cases, if powering life safety equipment. Think it's to do with the complexity.


Interesting. I wasn't aware of that. I suspect the life safety requirement could be gotten around with battery backup for egress lighting, and a few other things. Just don't power any elevators with it.


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## tjrobb (Feb 10, 2021)

FMEng said:


> Interesting. I wasn't aware of that. I suspect the life safety requirement could be gotten around with battery backup for egress lighting, and a few other things. Just don't power any elevators with it.



I WAS WRONG!

NFPA 110: 5.2.4 Allows all types of engines, or gas turbines.

I must have misremembered. But there is a caveat that if you use off-site fuel (normally, natural gas) is must have demonstrated reliability.


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## chausman (Feb 10, 2021)

FMEng said:


> Interesting. I wasn't aware of that. I suspect the life safety requirement could be gotten around with battery backup for egress lighting, and a few other things. Just don't power any elevators with it.



You actually can get battery backups (that meet life safety backup requirements) that are capable of running elevators, as long as the elevator doesn't regen back to the power line.


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## RonHebbard (Feb 10, 2021)

FMEng said:


> Interesting. I wasn't aware of that. I suspect the life safety requirement could be gotten around with battery backup for egress lighting, and a few other things. * Just don't power any elevators with it*.


One of our local hospitals has a bank of 6 elevators; 3 readily accessible to public, the other 3 facing into a non-public area and routinely used by hospital porters to transport Gurneys between floors. 

During power failures, as well as weekly scheduled / fully loaded test runs of the V12 emergency generator, 5 elevators descend to the lowest elevation affording fire egress, open their doors, and park. 
Only one of the non-public elevators is kept in service 24 / 7 / 365. 
Toodleoo! 
Ron Hebbard


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## macsound (Feb 21, 2021)

For a thought exercise, I thought about how many Tesla Power Walls it would take to power a theatre, but found their website so infuriating as to not provide any real documentation about what capabilities each battery had, I gave up.


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## egilson1 (Feb 21, 2021)

Buy all the crew new F150s with the 7.2kw on board power.
Hey, it’s working in Texas!


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