Help with dwelling calculation

Status
Not open for further replies.
crtemp

crtemp

Senior Member
Location
Wa state
I need to do a calculation for a house for an inspector. I see examples in Annex D and I was wondering if I can use the optional calculations if the house has wall heaters and not a heat pump. As soon as I know which method I should use I will do it and then post my results.
 
crtemp

crtemp

Senior Member
Location
Wa state
crtemp said:
just took a look at it and I will do the calculation based on that. I'll put my results up in a few minutes.
Click to expand...

Does this look correct?

1232 square feet
1232*3=3969 va
1500 small appliance * 2 = 3000 va
1500 laundry = 1500 va
Range = 9600 va
Dryer = 5500 va
Dishwasher = 1440 va
Hood Fan = 720 va
Water Heater = 6000 va
Septic pump = 1200 va

Total 32929 va

First 10000 @ 100% = 10000 va
22929 @ 40% = 9172 va
Total general loads = 19172 va


Heating load 8000 va * 40% = 3200 va


Total load = 22372 / 240 = 93 amps
 
crtemp

crtemp

Senior Member
Location
Wa state
Sorry...had some math wrong but same result

1232 square feet
1232*3=3696 va
1500 small appliance * 2 = 3000 va
1500 laundry = 1500 va
Range = 9600 va
Dryer = 5500 va
Dishwasher = 1440 va
Hood Fan = 720 va
Water Heater = 6000 va
Septic pump = 1200 va

Total 32656 va
First 10000 @ 100% = 10000 va
22656 @ 40% = 9062 va
Total general loads = 19062

Heating load 8000 va * 40% = 3200 va

Total load = 22262 / 240 = 93 amps
 
Chasman

Chasman

Member
Location
Colorado
Click on the link to Mike's web page. Look under free resources then industry resources.
there is a spread sheet for residential calculations that has aided me many times.
If the loads don't look right, be sure and go to the second page and delete pool loads.
 
crtemp

crtemp

Senior Member
Location
Wa state
Chasman said:
Click on the link to Mike's web page. Look under free resources then industry resources.
there is a spread sheet for residential calculations that has aided me many times.
If the loads don't look right, be sure and go to the second page and delete pool loads.
Click to expand...

I took a look at that but I couldn't figure out how to insert the wall heaters into the calculation. After reading the code calculation section I'm fairly sure my calculation is correct (I hope).
 
crtemp

crtemp

Senior Member
Location
Wa state
brother said:
Just remember, even if your calculation is below 100 amp, you still need a minimum of a 100 amp service disconnecting means for One family dwellings. NEC 230.79(C)
Click to expand...

Ya I know. This had a 125 amp breaker feeding it from a meter main. The inspector tagged it saying it was too small. I disagreed
 
Status
Not open for further replies.
Top