opinion

[Wiring2010]

Hi all,
I am turning down a rewire job to a Chinese restaurant because I do not like what I see on the existing panel. The connected loads are over the main which is a 200 amp breaker. There are two subpanels off the main panel. One subpanel is feed off a 30 amp two pole and the second subpanel is feed off a two pole 60 amp breaker. The owner doesn?t know what is on either subpanel. The owner wants to add additional ceiling lights but I am concerned that the main may pop. I cannot clamp the panel as this store had a fire a few months back (grease fire) and is under construction. I can only estimate by looking at what the ledger has for loads and figure from there.
Some facts; everything that is there now has worked in the past but now they want to add some huge ceiling fixtures plus additional cans ( 4 inch ) which is going to add to the load.
My question is how would you handle this? Would you count the number of circuit breakers and use that as a figure times a percentage? Thinking that not all the loads will be on at the same time. I was thinking of increasing the service but that would be costly but then I know I would have enough capacity for what is there.
So how would you handle the unknown meaning that that running current for the panel is not known but the connected load is and this connected load is more than the main.

 

[chris kennedy]

Since it is currently under construction, I would do a load calc as per 220.88 and see what that looked like, then weigh my options.

 

[iwire]

So how would you handle the unknown meaning that that running current for the panel is not known but the connected load is and this connected load is more than the main.

I would follow the NEC.

220.87 Determining Existing Loads. The calculation of a
feeder or service load for existing installations shall be
permitted to use actual maximum demand to determine the
existing load under all of the following conditions:

(1) The maximum demand data is available for a 1-year
period.

Exception: If the maximum demand data for a 1-year period
is not available, the calculated load shall be permitted
to be based on the maximum demand (measure of average
power demand over a 15-minute period) continuously recorded
over a minimum 30-day period using a recording
ammeter or power meter connected to the highest loaded
phase of the feeder or service, based on the initial loading
at the start of the recording. The recording shall reflect the
maximum demand of the feeder or service by being taken
when the building or space is occupied and shall include by
measurement or calculation the larger of the heating or
cooling equipment load, and other loads that may be periodic
in nature due to seasonal or similar conditions.

(2) The maximum demand at 125 percent plus the new
load does not exceed the ampacity of the feeder or
rating of the service.

(3) The feeder has overcurrent protection in accordance
with 240.4, and the service has overload protection in
accordance with 230.90.

 

[iwire]

Since it is currently under construction, I would do a load calc as per 220.88 and see what that looked like, then weigh my options.

That is a great way to go as well.

It happens I am worse at math than setting up a recording meter. :grin:

 

[Jlarson]

I'm having a da ja vue moment here.

 

[chris kennedy]

I'm having a da ja vue moment here.

I'm having a da ja vue moment here.

Hope that helps.:grin:

 

[Jlarson]

Hope that helps.:grin:

Thanks, thanks a lot.

 

[jxofaltrds]

Hi all,
I am turning down a rewire job to a Chinese restaurant because I do not like what I see on the existing panel. The connected loads are over the main which is a 200 amp breaker. There are two subpanels off the main panel. One subpanel is feed off a 30 amp two pole and the second subpanel is feed off a two pole 60 amp breaker. The owner doesn?t know what is on either subpanel. The owner wants to add additional ceiling lights but I am concerned that the main may pop. I cannot clamp the panel as this store had a fire a few months back (grease fire) and is under construction. I can only estimate by looking at what the ledger has for loads and figure from there.
Some facts; everything that is there now has worked in the past but now they want to add some huge ceiling fixtures plus additional cans ( 4 inch ) which is going to add to the load.
My question is how would you handle this? Would you count the number of circuit breakers and use that as a figure times a percentage? Thinking that not all the loads will be on at the same time. I was thinking of increasing the service but that would be costly but then I know I would have enough capacity for what is there.
So how would you handle the unknown meaning that that running current for the panel is not known but the connected load is and this connected load is more than the main.

"I am turning down***". Only you can know when and if to walk away. I like you; maybe; need the money. But I have and will walk away from 'bad' jobs.

I looked at the NEC Article #1.

Abbr. version of Article #1 is CYA.

 

[LarryFine]

Wiring, welcome to the forum!

The connected loads are over the main which is a 200 amp breaker.

... the connected load is and this connected load is more than the main.

Just so you know, that's almost universal, and is not an issue. That's why there is a main breaker.

 

[growler]

I am turning down a rewire job to a Chinese restaurant. this store had a fire a few months back (grease fire) and is under construction.
My question is how would you handle this?

The fact that it's a Chinese restaurant doesn't make any difference but the fact that they had a fire can make a lot of difference.

They may not be able to re-use existing panels anyway. It really depends on how close the were to the fire and if they got wet.

If it's a rewire then what's existing doesn't matter so much because it's what you are installing that counts. After a fire that's big enough to close a business they will normally need a new certificate of occupancy to re-open and this may require a lot of work and much of the building brough up to code.

The only thing I would be interested to know is if they have the money for a major remodel like this, it does get expensive. If they have money it's worth looking into and if they don't, why bother.

 

[petersonra]

I'd be inclined to do a load calculation and see what comes up.

You can't "legally" add the stuff if your calculated load is too high anyway, so I don't see how you can do the work at all without doing a load calculation, or using the alternate means as another poster mentioned.

 

[Wiring2010]

Thank you to all

Thank you to all

I just wanted to say thank you all for the input and it was well taken and edifying. The fire and the load along with the added equipment have made me pull away from this job. The owner wants the work done ASAP and I was not comfortable with not knowing the details. I did not know how much damage the fire did to the existing wiring and I could only get at some of the name plates on the equipment. The idea of looking at several months electrical bills is a good idea and I thank you for that idea.
The restaurant had a basement that was a spider web of romax with open wiring and a host of other violations of the code. One other interesting find at the restaurant was a second service panel, Federal Pacific, that had in it tucked away in the back of the panel a 30 amp circuit breaker. Along with the service entrance conductors was a single number 8 conductor that was attached to the 30 amp circuit breaker. The plug in side of the circuit breaker, the side that usually plugs into the bus bar, had a another number 8 conductor that went into a conduit along with two other conductors that are off a two pole 30 amp circuit breaker. All three connected to the line side of a 3 phase disconnect. When measuring for voltage between phases a, b , and c 240 volts was present . I only had a wiggly voltage tester. However measuring from each phase to ground I got between phases b and c to ground 120 volts however from phase a to ground I got 240 volts. Again that was with only my wiggly not my digital meter. I am thinking that a was the high leg of a delta system. I did not go any further do a preliminary investigation of what I was facing on this bid.
In the end I need the work but not this one. If I could scrap everything and start anew I would take the job.

Thanks again to all.

 

[LarryFine]

I only had a wiggly voltage tester. However measuring from each phase to ground I got between phases b and c to ground 120 volts however from phase a to ground I got 240 volts. Again that was with only my wiggly not my digital meter. I am thinking that a was the high leg of a delta system.

Sounds exactly right.

 

[renosteinke]

Your instinct to run was probably corect.

I have worked a number of Chinese restaurants, even built one new ... and I'm not to fond of working in even the one I built. FWIW, the concerns I have are also common to every other sort of restaurant I have worked in, with the exception of some free-standing, special-built chain operated places (think 'like McD'S')

With a major remodel, or an old place, eventually you wind up having a serious chat with the Power Company. Loads have grown greatly over the years, and there is simply no reason to settle for a 'delta' supply. You need that neutral.

If the place is operating, you need to check your voltages at lunchtime on the hottest day of the year. I've encountered maxed-out PoCo supples before, and that usually doesn't show itself until all the air conditioning is going full-bore.

Old gear? Lots of luck finding new breakers. By the time you get three of them, you've bough a new switchboard - and you still need to get the mounting busses made by the local machine shop.

Even after the place is open, all manner of stuff will be added, moved around, etc. You simply must allow room for at least 15% more breaker spaces than your wildest guess calls for. Especially allow for additional breakers serving the "Ansul" protected areas.

One reason for all these changes is that the Chinese, in particular, delight in getting their equipment from 'outside usual channels.' This means that one day a truck will arrive with all manner of bits and pieces in it. Some of the equipment will be fine; most will be incomplete, obsolete, made illegal by newer codes, or - in one memorable instance- stolen. Ultimately, the equipment you power will not be the stuff you were told to expect.

One final note: that big 4" PVC conduit you saw was not part of the electric- it holds the hoses to the soda fountain.

 

[stevenje]

Ultimately, the equipment you power will not be the stuff you were told to expect.

Spend the time and nail this down tight. Demand written nameplate ratings on every piece of equipment going into the project. A photograph of the equipment nameplate is even better. If you don't this it will come back and haunt you big time.

 

[GUNNING]

Good luck.

Good luck.

I have three rules,

complete projects,
go where the money is,
and

no restaurants.

Document everything.

They wait till the end to see how much money is left over to by needed equipment. Problem is it is the plumbers and carpenters and electricians and dry waller and ... money. Then they find out they have to pay for the food to sell which was the first week of payroll. Thats when they close there doors and make the second page of the local paper.

Get paid up front. Define exactly whats to be done. Don't get sucked in to design and build.

Restaurants enter bankruptcy faster than any other business.

I had a friend who asked a landlord how much he determines the rent should be for his commercial properties that are restaurants? His response was "a little more than they can make."