Service Calculations error?

[Christoph]

As far as I can tell this engineer (hired by project owner) put the appliances from table 220.42 on the Lighting load. Did he make a mistake?

Thanks

 

[david luchini]

Did he make a mistake?

Yes...

More than one mistake

 

[Christoph]

 

[Christoph]

Thought so. That changes everything. Panels to dwelling units for example. And also that pushes the overall service size from 1200 A to more than 1200 A which introduces a whole array of new requirements for the electrical room INDOOR in the basement which of course is a closet right now.

This thing is a headache already.

 

[david luchini]

Thought so. That changes everything. Panels to dwelling units for example. And also that pushes the overall service size from 1200 A to more than 1200 A which introduces a whole array of new requirements for the electrical room INDOOR in the basement which of course is a closet right now.

This thing is a headache already.

I come up with 120A using 220.82 (assuming "HVAC" is air conditioning, and assumed a range nameplate of 10.5kW)

Can't tell about the overall service size, as you didn't indicate how many units there were.

 

[Christoph]

I come up with 120A using 220.82 (assuming "HVAC" is air conditioning)

Can't tell about the overall service size, as you didn't indicate how many units there were.

Here is the full calc. A $2k engineering job:



The rest was delivered by email:

Based on the architectural plans and email correspondence you sent us, the following is the calculated electrical service size for the Hanover Square, apartment complex located in Pottstown, PA

Our calculation is based on 25 units with electric heat, cooking and hot water heating.

We recommend that the following:

• One (1), 1200 amp, 208/120 Volt, 3-phase, 4-wire, meter center, equipped with the following:

• 1200 amp, main disconnect, service entrance (SE) rated.
• Twenty-Five (25), 150 amp, 208/120 volt, 1-phase, 3-wire, meter sockets compatible with PECO standards.
• One (1), 250 amp, 200 amp, 208/120 volt, 3-phase, 4-wire, meter sockets for house and common area power.

• Each unit shall be equipped with a 150 amp, 208/120 volt, single phase, 3-wire residential load center, with 150 amp, main circuit breaker. The panel shall be equipped with a minimum of 30, single pole spaces and shall be equipped with bolt-on type circuit breakers.

• Two (2), 200 amp, 208/120 volt, 3-phase, 4-wire panel boards, equipped with 200 amp main circuit breakers, shall be provided for house and common area power.

• 1-150 amp, single phase, feeders (1.5” conduit, with 4-#1/0, Cu. and 1-#6, Cu., Ground) shall be extended from the centrally located meter center to each unit load center.

• 2-200 amp, three phase, feeders (2” conduit with 4-#3/0, Cu. and 1-#6, Cu., Ground) shall be extended from the centrally located meter center to a house panel on the 1^st floor level and to a house panel on the top floor level.

Please let me know if you have any questions or if you need anything else.

Thank you.

Sincerely,

 

[Christoph]

This is the info the customer gave initially:

I'd like a quote to provide electrical load calculations, identify panels sizes, and anything else that you would need to properly bid the job.

The power company has been contacted and there will be no gas appliances. They have indicated that it will be 3 phase-11/08. We have to install an 8x8 vault on the exterior.

The meter room is to be in the basement where each of the apartments will be metered individually. It probably makes sense to put a panel inside of each unit.

here are the loads of the appliances

heat pump- 460 V- 3 phase
hot water heater- can do either 208, 240, or 480
range-12,000 watts
microwave- 1000 watts
refridge- 120 V
washer/Dryer combo 120 V, 60 Hz
garbage disposal- 120V, 6.7 amps