size this service

[Jerseydaze]

commercial garage 3bays 1 large office 30x 15 currently has 100 amp single phase coming in want to cut office in half and separately meter also want ability to add air small roof unit? to garage .I am thinking two hundred amp coming in and splitting it to a 150 amp panel and a small 50 amp panel for the office opinions please

[nakulak]

no equip list ? ac amps/heat kw ? w/o list 200A will work fine, but it might not work for the tenant if they show up with some large equip they want to run.

[Jerseydaze]

Basical the garage is staying as is the only major load they may add is some sort of air conditioning there main consern is getting the office on its own meter .(The office will be about 10 outlets a surface fixture and a window Ac.

[tryinghard]

You should calc with an equipment list otherwise your really just instinctive calc’ing; an NEC base is a good starting point. Notice 220.12 and 220.14, at minimum the garage space should be calc’d at ½VA per sq ft and the office 3½VA. This listed 3½VA is all inclusive of the receptacles, unless calc’ing the receptacle quantity at 180VA plus the lighting is a greater value see 220.14(K) and of course (I).

[Rewire]

I would go with a 200A meterbase and panel for the garage and a 100A meterbase and panel for the office

[wawireguy]

I'd probably size the service to handle 3 lifts, BIG air compressor, steam cleaner.. Along with anything else you can think of that people will use if they don't know right now.

[Jerseydaze]

I would go with a 200A meterbase and panel for the garage and a 100A meterbase and panel for the office


If I did this would i size the grounds like a 300 amp sevrvice?

[tryinghard]

If I did this would i size the grounds like a 300 amp sevrvice?

No you size your grounding electrode conductor from 250.66. And you size your bonding from 250.104

[active1]

Some ideas for loads:

I would guess a 7.5 HP air compressor. If it is for mechanical repair it could be smaller but a body shop may be bigger. Auto body the air tools will run much more often and use more CFM. Body shops might have and air compressor drier. A body shop will or at least should get a paint booth. The lifts seem to allways be 2 pole 20a. The lift motors work for about 20 seconds raising and not for lowering. Just like everything elce many auto shops have computer terminals in the bays. Besides that figure a bay could use a few quads for things like battery chargers (car & cordless tool), smog testors, radios, drop lights, A/C equipment. Mig welder plugs in several locations is not uncomon. They will also have fixed equipment like brake legths or a pipe bender. Most shops have electric door openers.

Every shop will have small kitchen appliance loads like a beer frig, microwave, coffee maker, water cooler, maybe vending machines. Water heaters tend to be the small electric ones. What about a sign in front or show window lighting? Hope they have a TV in the waiting room. Add a few more for comunication equipment.

[Fulthrotl]

Some ideas for loads:

Every shop will have small kitchen appliance loads like a beer frig......
Add a few more for comunication equipment.

if you already have beer, what do you need to communicate for? :D
no need for those "don't forget the beer when you come over" calls....

[infinity]

Jersey are you just asking for some opinions or are you doing this job on your own? Wouldn't you need an engineer to sign off on this type of work in NJ?

[Jerseydaze]

Jersey are you just asking for some opinions or are you doing this job on your own? Wouldn't you need an engineer to sign off on this type of work in NJ?


What i love about this forum is i can ask some dumb questions anomalously I have always done primarily residential work and am not sure at what point you have to involve an engineer.