residential load calculation for 1800 sq ft house

[Stevenfyeager]

For a 1800 sq ft house with a gas furnace, but everything else is electric. (Typical elec range, w.h.,dryer, microwave, laundry,...) But it also has an outside 50 amp hot tub and an above ground 24 foot diameter pool. When I add the hot tub, I get more than 200 amps on an on line calculator, but I just added the 50 X 240 = 12,000 volt amps. Am I doing this right? Should I consider going to 400 amps? Thank you

 

[Dennis Alwon]

IMO, there is no way you need more than a 200 amp service without doing a calculation.

 

[kwired]

IMO, there is no way you need more than a 200 amp service without doing a calculation.

I understood he was attempting to do a calculation, but maybe did it wrong or the on line calculator he used did it wrong.

As far as using 50A for the hot tub, chances are actual nameplate amps was less then 50 though that alone wouldn't have made that huge of a difference in results assuming that if it called for a 50 amp circuit it probably draws at least 30-40 amps.

 

[Stevenfyeager]

I understood he was attempting to do a calculation, but maybe did it wrong or the on line calculator he used did it wrong.

As far as using 50A for the hot tub, chances are actual nameplate amps was less then 50 though that alone wouldn't have made that huge of a difference in results assuming that if it called for a 50 amp circuit it probably draws at least 30-40 amps.

The existing panel I will replace also has a 50 amp circuit to a detached garage. I've been talking with REMC about putting a separate meter for it, which they can do. You think I'm over thinking this?

 

[electricguy61]

The existing panel I will replace also has a 50 amp circuit to a detached garage. I've been talking with REMC about putting a separate meter for it, which they can do. You think I'm over thinking this?

Do a true load calculation: not breaker sizes, but actual loads. Use the service calculations in the code. But as was already stated, it's HIGHLY doubtful you need a service larger then 200amps.

And why why would anyone heat water with electricity when they have gas? Money to burn I guess?

 

[Stevenfyeager]

Do a true load calculation: not breaker sizes, but actual loads. Use the service calculations in the code. But as was already stated, it's HIGHLY doubtful you need a service larger then 200amps.

And why why would anyone heat water with electricity when they have gas? Money to burn I guess������

I did an "optional calculation" and got 167 amps (including garage, pool, hot tub) but get 275 amps doing the "standard calculation" These are using my old textbook. I am obviously doing something wrong.

 

[Dennis Alwon]

I did an "optional calculation" and got 167 amps (including garage, pool, hot tub) but get 275 amps doing the "standard calculation" These are using my old textbook. I am obviously doing something wrong.

There can be a big difference between optional and standard calcs-- I have no idea why both are allowed and you can use the smaller of the two

 

[electricguy61]

I did an "optional calculation" and got 167 amps (including garage, pool, hot tub) but get 275 amps doing the "standard calculation" These are using my old textbook. I am obviously doing something wrong.

Show your calculations and we can help.

 

[Dennis Alwon]

For a 1800 sq ft house with a gas furnace, but everything else is electric. (Typical elec range, w.h.,dryer, microwave, laundry,...) But it also has an outside 50 amp hot tub and an above ground 24 foot diameter pool. When I add the hot tub, I get more than 200 amps on an on line calculator, but I just added the 50 X 240 = 12,000 volt amps. Am I doing this right? Should I consider going to 400 amps? Thank you

No air conditioning? I still think 200 amp is good. I did a lenient standard calc and got 176 amps

 

[junkhound]

Like others have said, more that 200A at a residence is ultra rare.

Don't have a pool heater, but nave never tripped my 200Amain breaker, even during scenarios such as:

AC on, 24A 24 A
2 ea 20 A ovens going, 64A
2ea 15A microwaves 94A

DW is pressure washing the walk, 43A (4000 psi, 4gpm) 137A

Have 2 elec clothes dryers, both going, 45A total 182A

I'm welding (50A) - have tripped the welding 50A breaker. 232A

10A lights. 242A

Air compressor in barn happens to come on, 24A 266A

In 45 years where we have lived, have never tripped the 200A breaker, and the above scenario has probably come close to having happened, but continuous welding likely did not exceed the 2 min trip time for 130% of 200A QO.

Now, maybe if a pool heater was added to the mix ?

 

[Ponchik]

Remember a 200Amp breaker can continuously hold for 80% of its rating.

So, if there is a chance that the service will see 160A for longer than 3 hours, then you are still OK.

IMO, and as stated earlier 200Amp for your project is OK.

 

[user 100]

You think I'm over thinking this?

Yes, and I agree w/ the others. A 200a svc is perfectly fine w/ the loads you mentioned. And I would wonder too, as electricguy61 did above, why they didn't have gas for the wh, but also for dryer and range. It may cost a chunk to get it piped/vents installed if it isn't already in place for those other app's, but the conversion would more than pay for itself in the long run- electricity is expensive.

 

[Dennis Alwon]

Like others have said, more that 200A at a residence is ultra rare.

I have never said that because around here it is quite common to see 400 amps and occasionally 600 amps--did one not to long ago (600amps, ie.)

Large all electric houses, especially the custom ones often have 400 amps...

 

[GoldDigger]

I have never said that because around here it is quite common to see 400 amps and occasionally 600 amps--did one not to long ago (600amps, ie.)

Large all electric houses, especially the custom ones often have 400 amps...

Were those calculated to 400 or 600, or did the owner just want a more manly service?

I can see resistance heating adding a big lump, but a heat pump would already be mostly covered by the cooling load.

 

[kwired]

Yes, and I agree w/ the others. A 200a svc is perfectly fine w/ the loads you mentioned. And I would wonder too, as electricguy61 did above, why they didn't have gas for the wh, but also for dryer and range. It may cost a chunk to get it piped/vents installed if it isn't already in place for those other app's, but the conversion would more than pay for itself in the long run- electricity is expensive.

Some places electricity isn't too expensive. When gas prices were higher a few years ago some of the lower electric rate areas were pretty competitive or even less cost then gas for heating and water heating.

Winter months the electric rates actually do drop here, because all the demand is in summer months. This is partly an incentive to attract more winter load, operating costs are still there in winter whether the load is there or not.