# Re-calculating a motel service



## JohnR (Apr 12, 2010)

I haven't done a motel before, so bear with me. 
When calculating an existing motel, should I count up the existing outlets, etc, or use the nameplate loads of equipment in use?

I have an approximately 27 unit motel that has a 300A service, separated into 3- 100a panels. The owner says that in the summer months, all the mains trip at one time or another. Really!:laughing: 

So far, I used the name plate rating and the method of derating that allows first [email protected] 50%, next 20,001-100K at 40%, and last amount over 100K at 30%. ( I'm on the '05 code)

Came up with 394 amps at 240v single phase. Still don't have signage, lobby area, office equip, icemakers, soda machines etc. 


Going out now to get more info, sq ft, etc.


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## Bulldog1 (Oct 21, 2011)

JohnR said:


> I haven't done a motel before, so bear with me.
> When calculating an existing motel, should I count up the existing outlets, etc, or use the nameplate loads of equipment in use?
> 
> I have an approximately 27 unit motel that has a 300A service, separated into 3- 100a panels. The owner says that in the summer months, all the mains trip at one time or another. Really!:laughing:
> ...


I believe the receptacle load is included in you lighting load calculation on a motel.


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## Cletis (Aug 20, 2010)

I'd do optional and yes outlets included in sq footage calc. Anyhow, I'd just do a 615 amp service parallel and be done with it.


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## JohnR (Apr 12, 2010)

Ok, came up with lighting load of 10,802VA
Apartment with calculated load of 19,885 (standard calculation)

With just adding the two areas, and not the connected loads, I could do the entire thing with 150A service, that can't be correct.


If I add the connected loads, Tv, Iron, hair dryer, microwave, fridge, A/C-heat unit multiplied times each room, and then add in the largest motor, furnace, hot water, ice maker, soda machine etc. The load comes to 244,071VA
If I apply T220.42 I get 85,220.9va, add in the apartment =105105.9va
which is [email protected], or 292A @208v 

Would it be worth it to go to 3ph if I could, seeing that the loads are mostly single phase, and the 240v loads are also 208v rated? Not sure about the submersible well pump though.


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## CTshockhazard (Aug 28, 2009)

Maybe if they just unplug all the bed vibrators at this 'short stay' place the mains will hold. :laughing:

The motels in this area are usually owned by people that don't want to spend the money on either a 500A 1Ø or a 300A 3Ø service! :no::whistling2:

You'd have to run all the numbers to see how the cost to go to 3Ø will compare to the cost to up the 1Ø service size. If it's OH, 3Ø will probably be cheaper.

Either way if you do get it and need help, I'm not that busy :thumbsup:


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## JohnR (Apr 12, 2010)

Thanks CT, I will need help if I get it, I have an "in", but don't know just when the guy will do it or how good my "in" is. LOL Told him that it would be sizable and he didn't blink yet, I hear he is the paying kind so.... 

Probably won't be till spring, the main breakers are outside, and that is fine for keeping the mains cool so they don't trip.:jester::whistling2: Actually the heat load is less than the A/C load. He is doing an add on to the front, some dormers, and will be adding a few more can lights, probably cfl's in them. 

He says he is trying to have a nicer motel so that he gets longer term renters. Will have to add travel to this bid, it is within spitting distance of RI, no easy way to get there.


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## CTshockhazard (Aug 28, 2009)

JohnR said:


> Will have to add travel to this bid, it is within spitting distance of RI, no easy way to get there.


Have tools, will travel.

Good luck with the bidding.


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## kbsparky (Sep 20, 2007)

Motels are notorious for having more load than "calculated," since if the entire place is full, all the A/C units (or electric heating in winter) can be on at the same time.

I would NOT apply any demand factors if upgrading to a larger service to replace one that trips regularly.


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## JohnR (Apr 12, 2010)

Thanks KB, will take that into account. Never dealt much with motels but can see that the potential for massive loads at once are a real possibility. From what I see, Cletis with his, off the cuff? 615A service might not be that far off reality.

Right now, I am waiting for monday to talk with the POCO, and for the owner to email me copies of his electric bills 2 summer, 2 winter.


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## denny3992 (Jul 12, 2010)

27 units thats only 11 a per unit?

Are they ptacs or ahus for heat and cool?

Plus common areas

Gotta be more than 300a!

Just my opinion


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## Cletis (Aug 20, 2010)

denny3992 said:


> 27 units thats only 11 a per unit?
> 
> Are they ptacs or ahus for heat and cool?
> 
> ...


What if it's full and 97F and humid out? I could see at least 5000 watts per unit being drawn if only for a short period which would be 190kva which would be 791 amps single phase ??? 

What kind of motel is this anyhow? rent by the hour, live in, vagabonds and drug dealers ?


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## garfield (Jul 30, 2009)

Cletis said:


> What if it's full and 97F and humid out? I could see at least 5000 watts per unit being drawn if only for a short period which would be 190kva which would be 791 amps single phase ???
> 
> What kind of motel is this anyhow? rent by the hour, live in, vagabonds and drug dealers ?


Just look at the demand on the bill. That'll make you more comfortable normally.


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## JohnR (Apr 12, 2010)

denny3992 said:


> 27 units thats only 11 a per unit?
> 
> Are they *ptacs *or ahus for heat and cool?
> 
> ...


Don't know what that is, They are through the wall units heat pump stand alone. Not AHU's The label on the one I looked at said 10.2A 240/208V but in another area depending on model could be around 4.2A? If I can, I will post the pic of the nameplate.

300A is the existing service separated into 3- 100A panels. All of these tripped last summer he said, but only when the place was full. 
Using de-rating, I come up with 437A right now single phase. Don't see how the place didn't roast something.

Oh, did I mention that all the feeders run through the attic? I will have to run at least one more conduit, and feeder to split the front area panel.


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## JohnR (Apr 12, 2010)

Cletis, Live in, by the night. He won't traffic in the by the hour clientele.


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## Elephante (Nov 16, 2011)

I agree look at the demand on the bill for the hottest month and coldest month to give you an idea.


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## Vintage Sounds (Oct 23, 2009)

PTAC = packaged terminal air conditioner. The typical hotel room AC/heat combination unit.


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