Three bathroom receptacles...

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dhsvcs

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miami
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electrician
I have a job with 3 bathroom receptacles, each bathroom has a receptacle on it's own breaker..There are multiple panels ( 320/400 A ) service.
All 3 recepts come from one panel. Since I have to work with connected loads and ( I think ) I can only derate the service as a whole ( standard or optional load calc ) ,
Highly unlikely with 3 bathrooms that all 3 receptacles would be being used at the same time. For a demand load, what would be the requirement ror each receptacle ?
Can I use 180 VA per receptacle ?
Thanx, dhsvcs
 
You can... but you dont have to. See 220.41(1).... If this is a dwelling unit and according to 2023 code.
 
Is this a dwelling or other type of occupancy?

Dwelling, the load for these is to be included in the general lighting load of 3 VA per square foot.

Other applications, with no dedicated or fixed load to be plugged in they are 180VA each.
 
I am figuring this is a Dwelling unit! You need not count anything for these three receptacles. 210.11(C)(3) and 220.14(J)(1).
 
If I am correct, even though it's a residence, I have 3 breakers on a 320/400 A meter. I believe I have to do a connected load on for each load center (3) in addition to the whole service calculation. This is for 2017 code. I believe there is a minimum of de-rating or diversity for each feeding breaker to load center combination....That is why 180 va per BATHROOM receptacle as a "general purpose" receptacle becomes beneficial...
Thanx, dhsvcs
 
I was told by an electrical engineer that with 3 main breakers, even in a residence, that each main breaker has to be able to handle it's connected load..
 
dhsvcs said:
If I am correct, even though it's a residence, I have 3 breakers on a 320/400 A meter. I believe I have to do a connected load on for each load center (3) in addition to the whole service calculation. This is for 2017 code. I believe there is a minimum of de-rating or diversity for each feeding breaker to load center combination....That is why 180 va per BATHROOM receptacle as a "general purpose" receptacle becomes beneficial...
Thanx, dhsvcs
Click to expand...
That is not correct. The answer was given above. Read the section that was quoted.
dhsvcs said:
I was told by an electrical engineer that with 3 main breakers, even in a residence, that each main breaker has to be able to handle it's connected load..
Click to expand...
Of course it does but when you use the calculation according to the NEC there is no receptacle load for a bathroom. It is included in the 3 watts per sq.ft.

You can never load a panel higher than the breaker that protects it.
 
How do I figure out the connected load to a load center that has 3 separate 20 amp receptacles each with their own breaker ?
I understand that the load calc for the service is the combination of all 3 load centers, but what value do I give on my connected load sheet for that particular panel ? That is why I believe the 180 VA per receptacle becomes beneficial.

If I am correct, even in a residence if you have multiple main breakers, each breaker has to have a connected load calculation and complying breaker size...
 
They even allow for 2 bathrooms on an outlet circuit. Says something about the nature of the loads in resi.
 
Still looking for connected load value for each bathroom receptacle on 2nd floor panel spread sheet...( 1 of 3 load centers )...
:):)
I believe that would be 180 VA for each receptacle...(as long as it's not a dedicated receptacle with a higher load...)
 
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Also, I believe, in the 2007 code, for bathroom counter receptacles (only), you can have over 10 on 1 circuit.
 
dhsvcs said:
Also, I believe, in the 2007 code, for bathroom counter receptacles (only), you can have over 10 on 1 circuit.
Click to expand...
Really? That is a factoid worth knowing. It takes a while to get ones mind around being rated by occupancy.
 
dhsvcs said:
Still looking for connected load value for each bathroom receptacle on 2nd floor panel spread sheet...( 1 of 3 load centers )...
:):)
I believe that would be 180 VA for each receptacle...(as long as it's not a dedicated receptacle with a higher load...)
Click to expand...

You refuse to accept what was told to you so figure 180va per.... Not sure what you want.
 
Not that this helps directly or maybe it will but we saw a thread here the other day was fussing over a couple points but in the end it really didnt change much, I am always curious, if you add the higher figure does it change the demand enough to change the design? I like the term optional load calc.
 
dhsvcs said:
Still looking for connected load value for each bathroom receptacle on 2nd floor panel spread sheet...( 1 of 3 load centers )...
:):)
I believe that would be 180 VA for each receptacle...(as long as it's not a dedicated receptacle with a higher load...)
Click to expand...
Your connected load only applies to the service as far as calculations. The calculation is to size the service for the proper conductors and OCPD. You never have to count each subpanel's individual load in the calulations, just total load. If it's a split service such as a 400A/320A , these are not actually subpanels but still the total load is counted. When the calculations are done using the 3kva per sq ft, the bath receptacles are included, no reason to count them twice.
Now having said that, if you're using multiple panels, common sense will tell you not to overload any of the panels.
 
dhsvcs said:
I was told by an electrical engineer that with 3 main breakers, even in a residence, that each main breaker has to be able to handle it's connected load..
Click to expand...
That is not correct, from a Code perspective. Each main breaker and every sub breaker has to be able to handle its calculated load.
 
Everything has to handle its calculated load. Right down to the fixture wires. UL insures it is legal on a legal circuit, its fundamentally code compliant. Not only for thermal but the equipment relies on the system breaker for short circuit it must comply with recognized agency, it seems this is an extension of fundamental code. Cant list it if it doesnt have approved wire size etc. Got to put a cord legal with code on it.
 
I apologize for insisting on 180 va/bathroom receptacle. i am just trying to correctly grasp the procedure to calculate the correct load for a real residential project.

The meter is 240 v single phase 3 wire 400 A/320 A continuous meter.
There are 2 mains, each with a 200 A breaker. The 1st main feeds an 8 circuit bus in the G.E. enclosure itself. It also has pass-thru lugs at the bottom of the bus which I may use in the future to feed a pool panel.
I want to feed the 2nd floor panel with a 100 A breaker from the 8 circuit "mini-panel" ( over 25 ft away..10 / 25 ft tap rule ) and keep the rest of load available for future swimming pool and car charger. The 2nd floor is approximately
1400 sq ft and has 3 bathrooms, each "counter" receptacle separately fed by it's own 20 A breaker. It also has the 2nd floor AHU, part of a heat pump system without a back-up heater. ( job is in south Florida, owner does not believe a back-up heater is necessary..) There is minimal load on the upstairs panel, so the future looks bright for the future pool equipment and possibly a car charger. I would ( if this is correct ) figure this at 1400 sq ft at 3 watts / ft.
There would be no range or water heater on this panel, but the 2nd floor does have a washer and a dryer. Could I also use Sokolnik's
spread sheet to figure the wire size to feed the 125 A main lug panel ? (using a 30 space 30 ckt full size brkr panel )

Do I do a standard or optional load calc on the 100 amp breaker for calculating the feed to the 2nd floor panel ?
And do I do a standard or optional calc for the 200 amp breaker feeding the 8 ckt panel including the loads of the
100 Amp brkr feeding the 2nd floor panel ?

The first floor includes the kitchen and is approx 1650 sq ft. I would feed this at 200 Amps ( may be less..depending on calcs...) the breaker for the 1st floor has not been purchased yet. The property is presently unoccupied and is being fed by a temporary service while the electrical plans are being revised. It will feed the 2 heat pump condensers, the 1st floor ahu and asstd kitchen and other appliances. Do I calculate this at 1650 sq ft @ 3 watts a sq ft. ? Can I use Sokolik's spreadsheet to calculate the feeder size ? Do I need to use standard or can I use optional calculation ?
Can I use the calculated load for feeder sizing ?

Finally, when this is done, do I do a TOTAL calculation for the entire service, including all items at 3050 sq ft ?

Sorry about the dumb questions, but I was told this was the way to do the calcs by an electrical engineer I have known for over 15 years... I am 70 yrs old and still learning.....

Thanx, dhsvcs
 
Technically, you do three calculations. A total one, and one for each panel. The total one can be the optional. The separate panels probably need to use the standard unkess each feeds what is defined as a dwelling.

Another example of circuits with zero load would would be a dedicated circuit that feeds the required outside receptacles. You can assign a load to these if you want, but code says zero for dwellings. And random 15 amp load on a panel ends up being in the noise...
 
Am I correct using the 1400 sq ft x 3 for the 2nd floor calc ( do I include 2 small appliance ckts for 2nd floor calc ? ), 1650 x 3 w for 1st floor calc, and treating the the 2nd floor calc (not having a water heater or range) and having no electrical load the same as a gas appliance ( no load 2nd floor) ?

And the 1st floor calculation.. ... do i need to add a laundry ckt ?

thanx..dhsvcs
 
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