Load Calc with Shower Steam Unit

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Chamuit

Senior Member
Location
Texas
Would this be correct or right for calcs on a single family with a steam unit in the shower?

Non-Motor Loads
3VA per ft? 3119ft? 9357VA
Appliance circuits 2ea 3000VA
Laundry 1500VA
Refrigerator 1344VA
Dish Washer 1080VA
Dryer 4500VA
Steam Unit for Shower 15000 VA
Water Heater gas 0VA
Microwave 1000VA
Range/Oven 8000VA

TOTAL 44781VA
1st 10kVA 10000VA
Remainder (34781VA) @ 40% 13912.4VA

Motor Loads
1st Air Conditioner 125% 40A/240V 9600VA 12000VA
2nd Air Conditioner 100% 24A/240V 5760VA 5760VA
1st Furnace 125% 12A /20V 1440VA 1800VA
2nd Furnace 100% 12A/120V 1440VA 1440VA
Pool Motor 100% 12.5A/240V 2400VA 2400VA
47312.4 VA
?240 V
197A
 

Npstewart

Senior Member
http://forums.mikeholt.com/showthread.php?t=127901

Check that thread out from yesterday, Charlie b spelled it out pretty well. Add your steam shower separately.

It appears your using the nameplate value for a lot of your values, I would be careful doing that. At least use 1500VA for your microwave & 5000 VA for your dryer & 1500VA for your dishwasher. All those appliances are easily replaceable.

Just my opinion.
 

Npstewart

Senior Member
Heres a PDF of my load calculation I typically use for residential.

The bottom may be the most confusing thing, but basically you subtract 10KW from your loads, then take the remainder at 40%.
 

suemarkp

Senior Member
Location
Kent, WA
Occupation
Engineer
That is using the optional calculation. I don't think you can take the range at 8KW when using the optional calculation -- needs to be nameplate value. I think the OP will get a much smaller load calculation with the Optional Calculation since a 40% factor applies to most items. With the standard calculation, it is going in at 100%, or 75% if you can happen to find 3 other appliances to use for the 4 or more demand.
 

Npstewart

Senior Member
the optional load calculation does make you use name plate value for the range, however your wrong about the 75% demand factor. See example D2(a), page 1344 if you have the handbook.

The demand factor for the optional calculation is the calculated VA - 10KW + REMAINDER @ 40%
 

Chamuit

Senior Member
Location
Texas
The EE I use sometimes e-mailed back and said that I needed to add the steam unit in the second half with my A/C's which puts my calc at 245A-ish.

He also said that the original calc at 197 would make them (his firm) go ahead and call for a 400A service. CYA thing for them.
 

Chamuit

Senior Member
Location
Texas
http://forums.mikeholt.com/showthread.php?t=127901

Check that thread out from yesterday, Charlie b spelled it out pretty well. Add your steam shower separately.

It appears your using the nameplate value for a lot of your values, I would be careful doing that. At least use 1500VA for your microwave & 5000 VA for your dryer & 1500VA for your dishwasher. All those appliances are easily replaceable.

Just my opinion.
I had looked at that. I still wasn't sure how to handle the Steam Unit. ;)
 

Chamuit

Senior Member
Location
Texas
the optional load calculation does make you use name plate value for the range, however your wrong about the 75% demand factor. See example D2(a), page 1344 if you have the handbook.

The demand factor for the optional calculation is the calculated VA - 10KW + REMAINDER @ 40%
The stove was 7.5Kw @240V. I just left the 8Kw.
 

suemarkp

Senior Member
Location
Kent, WA
Occupation
Engineer
the optional load calculation does make you use name plate value for the range, however your wrong about the 75% demand factor. See example D2(a), page 1344 if you have the handbook.

The demand factor for the optional calculation is the calculated VA - 10KW + REMAINDER @ 40%
The 75% factor I was mentioning is for the STANDARD calculation when you have 4 or more appliances fastened in place [220.53].
 
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