Please help? I'm not sure if my electrician is calculating correctly..

[evdryst]

Lighting, small appliance, & laundry = 10350va...demand = 5573
Appliances = 4563 ..........................................demand = 3422 (I left out fridge, could probably leave out freezer, as it is included in small appliance load.)
Range.........................................................................= 8000
A/C.............................................................................= 6500

Total = 23495 = 98A @ 240V

Aha, I see. Shouldn't I also add 25% of the biggest motor? (The AC)?

Thanks.

 

[evdryst]

I tend to be skeptical when I hear or see someone make a statement along the lines of, “I can’t do that because it’s against the rules.” May I ask exactly how you came to believe that the HOA would not allow you to increase your service to 200 amps? Did you submit an application to the HOA and did they turn it down? I can’t imagine that the HOA contract has a line item that says, “Your electric service is, and shall remain, 100 amps, and you are not permitted to increase it.” So let’s set aside anything that anyone told you, and let me ask this: Have you personally seen, in writing, a statement to the effect that the HOA will not permit any service upgrades?

You're right, of course, I haven't applied; I've been going on heresy (by my contractor who have done renos on quite a few units in the community, so it's not completely myth ) I did just shoot the president of the HOA an email though, to get a feel for it.

From what I understand though, even if I do get HOA permission, is that I'll have to get a new service to my townhouse from the street, just for me, since the building (I'm guessing 10 townhouses) share a 400 AMP service between the lot of them?!? This all sounds a little improbable. Who should I ask? The department of water and power perhaps?

I was going to find all of this out, but I was hoping my electrician is wrong and I could get away with my existing 100AMP service..

 

[GoldDigger]

Aha, I see. Shouldn't I also add 25% of the biggest motor? (The AC)?

Thanks.

The Minimum Circuit Ampacity (MCA) number on the nameplate of the AC already includes the 125% of largest motor calculation. There is generally more than one motor in an A/C unit (compressor and fan).

 

[wwhitney]

I took a look at the A/C and it's a 4 ton (Aspen Manufacturing CE48F34-175L-004).

That part number is apparently just for the evaporator coil (the interior part that goes inside your air handler). What are the make, model number, and nameplate data on the exterior unit? That's the part with the compressor motor that is the largest electric draw.

Cheers, Wayne

 

[evdryst]

That part number is apparently just for the evaporator coil (the interior part that goes inside your air handler). What are the make, model number, and nameplate data on the exterior unit? That's the part with the compressor motor that is the largest electric draw.

Cheers, Wayne

And by exterior unit you mean the thing on the roof?

I'll ask my contractor if he can get up there. Makes me wonder how the electrician knew what to fill in on the calculations. Can one look at the stuff that is in the closet and make an educated guess?

 

[wwhitney]

And by exterior unit you mean the thing on the roof?

Could be. They are usually roughly cubic in shape with lots of louvers on all the sides and the top. [Do a google image search on a/c unit.]

Cheers, Wayne

 

[evdryst]

Could be. They are usually roughly cubic in shape with lots of louvers on all the sides and the top. [Do a google image search on a/c unit.]

Cheers, Wayne

Sorry.. that was meant as a rhetorical question. Yep, it's on the roof. I still have contact with the previous owner; I'll ask if he has an invoice/details. He was a bit stingy with other stuff, so lets hope it's a small one :lol:

 

[jim dungar]

... since the building (I'm guessing 10 townhouses) share a 400 AMP service between the lot of them?!? This all sounds a little improbable. Who should I ask? The department of water and power perhaps?

It is quite common for there to be a multi-meter center, where a single utility feeder is brought to a building and then it is broken down to an individual meter for each unit. In this case you would be limited to the maximum size breaker that can be installed in the meter assembly, which in your case is likely 100A.

 

[Dennis Alwon]

Dennis Alwon, would you mind explaining why I can't use column C, 1 appliance = 8000 for the oven?

Thanks all.

If you use optional calculation Table 220.55 does not apply

220.82(B) General Loads. The general calculated load shall be
not less than 100 percent of the first 10 kVA plus 40 percent
of the remainder of the following loads:
(1) 33 volt-amperes/m2 or 3 volt-amperes/ft2 for general
lighting and general-use receptacles. The floor area for
each floor shall be calculated from the outside dimensions
of the dwelling unit. The calculated floor area
shall not include open porches, garages, or unused or
unfinished spaces not adaptable for future use.
(2) 1500 volt-amperes for each 2-wire, 20-ampere smallappliance
branch circuit and each laundry branch circuit
covered in 210.11(C)(1) and (C)(2).
(3) The nameplate rating of the following:
a. All appliances that are fastened in place, permanently
connected, or located to be on a specific circuit
b. Ranges, wall-mounted ovens, counter-mounted cooking
units
c. Clothes dryers that are not connected to the laundry
branch circuit specified in item (2)
d. Water heaters

 

[evdryst]

That part number is apparently just for the evaporator coil (the interior part that goes inside your air handler). What are the make, model number, and nameplate data on the exterior unit? That's the part with the compressor motor that is the largest electric draw.

Cheers, Wayne

I climbed out a tiny window onto the roof to get this :lol:

Goodman Manufacturing Company
Model: ASX160421FA Serial Number: NA
AC Volts: 208-230 Phase: 1 Hertz: 60
Voltage Range: Min: 197 Max: 253
Max. Fuse Amps or Max. Circuit Breaker: 40
(Time delay fuse or hacr circuit breaker required)
Min. Circuit Amps: 23.5
Fan Motor FLA: 1.1 H.P.: 1/6
Compressor RLA: 17.9 LRA: 112

I need to add the Air Handler Unit to the AC's VA for the calculations, right? Would this be it?
Goodman Manufacturing Company
Certified as a Forced Air Furnace: CAT1
Model: AMH80804BXBB
Power Supply: 115 Volt 1 Phase 60 Hertz
Less than 12 amps.

Thanks.

 

[Dennis Alwon]

The min circuit ampacity has 125% built into it so you don't use that. So you have 17.9 + 12 amps = 30 amps or 7200 watts

 

[wwhitney]

AC Volts: 208-230 Min. Circuit Amps: 23.5

So that's 240V * 23.5A = 5,640 VA

Power Supply: 115 Volt Less than 12 amps.

And that one's 120V * 12A = 1,440VA

For a total of 7,080 VA.

Cheers, Wayne

 

[evdryst]

The min circuit ampacity has 125% built into it so you don't use that. So you have 17.9 + 12 amps = 30 amps or 7200 watts

Did you mean (17.9 * 240) + (12 * 120) perhaps?

 

[evdryst]

Almost there, I hope..

Almost there, I hope..

So if I understand it correctly, this would be the calcs for the AC and blower for Standard and Optional?

Standard:
A/C: 240V * 23.5A = 5,640VA
Motor: 120V * 12A = 1,440VA
= 7080VA, and I don't have to add 25% of anything in anywhere, since the MCA already includes it.

Optional:
A/C: 240V * 17.9 = 4296VA
Motor: 120V * 12A = 1440VA
= 5736VA, and I don't have to add 25% of anything anywhere since that's just only used in the standard calculation.

If this is the case, Optional is definitely better. In fact, I can get the single oven + speedcook we wanted, in lieu of the microwave oven combo.

Could anyone please double check me?

Lighting	1950	3	5850
Small appliances	2	1500	3000
Laundry	1	1500	1500
			10350	10350
A/C		17.9	240	4296
Blower		12	120	1440
Fridge			180
Freezer			565
Dishwasher			1300
Wine fridge			144
Hood			610
Disposal			1224
Garage			720
			4743	4743
Single oven and speedcook	1	13500	13500
				23173.2
				96.555

Thanks.

 

[wwhitney]

Optional:
A/C: 240V * 17.9 = 4296VA

You have to add the 1.1A for the fan on the A/C unit itself. As for the rest of it, that's beyond my experience.

Cheers, Wayne

P.S. Notice that 23.5 = (1.25) * 17.9 + 1.1. That's how MCA is determined.

 

[JFletcher]

If you wind up over 100A, and the inspector wont budge, cant upgrade the service, etc etc, ditch the disposal until a later time; that frees up 5A @240V

 

[kwired]

The min circuit ampacity has 125% built into it so you don't use that. So you have 17.9 + 12 amps = 30 amps or 7200 watts

indoor air handler was only 120 volts.

 

[evdryst]

I'm at 97!

I'm at 97!

Thanks so much for all the help and advice. This forum is amazing