old building panelboard

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bbhatt

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hello,

i'd appreciate some advice in the following situation.

i am building a restaurant in an old building that the landlord had fixed-up.
having finished the plumbing/furniture/and rough-in electrical wiring, the
contractor then proceeded to install a new (additional) panelboard specific to my equipment. (my panelboard requirements are 225A 110V single-phase three wire 42 circuit)

he looked at the old panelboard (supposed to be rated 400A) and reported that the service is two phase 110v and single phase 208 (for an old unused elevator). And also said the existing Sq.D panelboard label says 175A. (I believe my MEP designer made a mistake in assuming a 400A service?).

question-1: is it normal to have two-phase 110 and a single 208 in a buidling?

question-2:Is there any way to extract 200+ amp from existing except by re-doing the old panel? Is the landlord responsible for this work? (i am quoted a price of about $20K to re-do the old panel).

The service from the street is over three 250MP cables for 110v and 208v.

thank you very much.
 
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bbhatt said:
question-1: is it normal to have two-phase 110 and a single 208 in a buidling?

question-2:Is there any way to extract 200+ amp from existing except by re-doing the old panel? Is the landlord responsible for this work? (i am quoted a price of about $20K to re-do the old panel).

The service from the street is over three 250MP cables for 110v and 208v.

thank you very much.
Click to expand...

Very common to find 120/240 single phase, and 120/208, or straight 208 or 240 3 phase. (two seperate services) Dont know what a two-phase 110 and a single 208 is, unless there is some confusion over a high-leg (center-tapped) delta, which would also be fairly common. (As a single service) and sounds as if you have a 120/240 delta, and that '208' leg would be 180-210 or so depending on the tap position in the windings.

As for your load - only way to know is a load calc of existing and new.

And it not un-common for someone drawing up plans, or even an electrical engineer to get bunk info - as an electrician I would confirm that. If you were an electrician - you could to. It might be time you called one.
 
Oh, and normaly in a Tenant Improvement (TI), it is the Tenant who is responcable for up-grades to accomadate service required to facilitate the tenant area, the landlord may take pity, and chip in, but not required.
 
bbhatt said:
(my panelboard requirements are 225A 110V single-phase three wire 42 circuit)
he looked at the old panelboard (supposed to be rated 400A) and reported that the service is two phase 110v and single phase 208 (for an old unused elevator). And also said the existing Sq.D panelboard label says 175A. (I believe my MEP designer made a mistake in assuming a 400A service?).

question-1: is it normal to have two-phase 110 and a single 208 in a buidling?
Click to expand...

Answer NO... it sounds like your contractor is not a qualified electrician or did not explain correctly... What determines service designation is the voltage measured from line to line... not line to neutral.

Lines which measure 110-120v to neutral (or ground) will usually measure either 208v or 240v to each other. If there is a 3rd wire with 208v to neutral it will usually measure 240v to the other 2 which means you probably have a 3 phase 240v delta service. (If all 3 lines measured 120v to neutral and 208 to each other it would be a 3 phase 208v wye service)

"question-2:Is there any way to extract 200+ amp from existing except by re-doing the old panel? Is the landlord responsible for this work? (i am quoted a price of about $20K to re-do the old panel)."

240v 175A 3 phase = 525A @ 240v single phase. (3x175A=525A)
Unfortunately you can only use one of the phases for 120v circuits (175A @ 240v = 350amps @ 120v)
If you have 240v appliances they may be able to make use of the other 2 phases... but watch out: appliances that state the highest phase to ground not to exceed 200v can't!!

"service from the street is over three 250MP cables for 110v & 208v."
I'll assume 250mcm aluminum wires (consistent with 170A Service)

Hire a qualified electrician or engineer don't let your carpenter do it.

When asking for quotes show all your information including blueprints, a list of fixtures and appliances with spec sheets.
ASK FOR IDEAS... A good electrician will save you money by suggesting alternatives like using multiple panels in strategic locations.

Check with companies that specialize in industrial kitchens... their experience can save huge amounts of time and money... often when doing upgrades they get nice used equipment for free and will give it to you for the cost of the install.
 
thank you gentlemen for all the replies, based on what i measure at the site and how old this building is: it looks like its a 3-phase 4-wire (with B-stinger) system. By the way, I understand your general suggestions that I should not let a carpenter do the job. But I think he is OK, it was my fault that I had not translated his words correctly in my post.

since the b-stinger tap is unused (240v) is it possible to use a step-down transformer to get additional juice out of the panel?
 
Ahhhh... Dave, Thats a pretty simplistic method to explain a faily intricate calculation - and a bit misleading to the non-electrician. (See Annex D)

bbhatt, I assume this is your resturaunt? I am not a carpenter, although I often carry a hammer. And although I have seen a lot of plumbing done before, I am not a plumber. Likewise, a carpenter is not an electrician. And IMO what I have seen them do with electrical is totally frightening for the most part. You need someone on site with a much better understanding of the issue at hand.

"If you think hiring a proffessional is expensive - try hiring an amature."

I assume that you are putting together a 50% plus electrical appliance Kitchen? And that 100% of your income will be dependant on reliable electrical supply. No lights / no customers - No refers / no food - No power - no coffee. etc, etc... Likewise, if you were to have a fire, you would not only be lossing your buisiness, you would be liable for the work done within your unit. (Most states - the landlord will post a non-responcabily notice for any construction) BTW the National Fire Protection Agency writes our electrical codes, and for a reason.

Bottom line is - you CAN NOT get this resolved over the internet.... You need a professional Electrician, a licensed one on site. It may be cheaper in the long run.
 
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