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wigi

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An elect. has 171 amps as his calculated load ,this is a commercial building. He install 2/0 awg for the service conductors, with a main lug 200 amp panel I told him he need 3/0 for the wire cus its not a dwelling. You think I'm wrong or right as close as we can follw code.
 
Where is the disconnecting means and what is it's rated OCPD? Is it a fused disconnect, enclosed breaker, or is there going to be 6 or less breakers in the MLO panel?

Roger
 
There is no c.b. or fuses only main lugs has 6 bkrs 2-50,1-100,3-30, this is the main pnl for the building next to meter can
 
Wigi, this being the case, the service could be permitted at 175 amps and the 2/0 would be OK.

I agree with you that if there was a 200 main, the 2/0 conductors for a commercial installation could not be used, Table 310.15(B)(6) would not be applicable.

Roger
 
As an inspector will it be ok when all the equipment is rated at 200amp and the wire is rated at 195 . Remember, nobody will garant, the owner may someday add load to service,
 
Wigi, what happens after the inspection can not be controlled.

Take a fused disconnect for example.

Let's say we have a 150 amp service where the Main is a fused disconnect properly fused with 150 amp fuses, the disconnect itself would be rated at 200 amps and capable of accepting 200 amp fuses, these 150 amp fuses could be changed by the user at any time in the future, but an inspector could not reject the installation.

Roger
 
But in this situation it can still be control,cuz the ahj is still going to inspected and its a new commercial blding
 
Wigi, at the time of this inspection, the 175 amp service will be legal, and assuming it will be violated down the road at sometime is not enforcible.

How are you going to assure the inspector that a 7th breaker will not be installed a some point in time even if the conductors are increased in size.

Is the inspector going to drop by everyday from now on?

Roger
 
wigi said:
it can still be control
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The AHJ is not the control, the NEC is the control that the AHJ enforces.

The NEC says that the service is sized based on the calculated load.

Remember NEC 90.1(B)
90.1 Purpose
(B) Adequacy This Code contains provisions that are considered necessary for safety. Compliance therewith and proper maintenance results in an installation that is essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use.
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If the calculation of 171 Amps is correct, then 2/0 Cu satisfies Code.

As an aside, I get customers who will demand the lowest price, inspite of my best attempts to communicate the limitation of what they are buying.

If my customer is comfortable with an underpowered car (underpowered by comparison to a "high powered" car), then they just don't have any more power than what the engine puts out. Their car will not have a huge power reserve at highway speed. They have to drive in a manner that doesn't require sudden & quick passing. And even with gentler driving, will possibly burn up the engine quicker.
 
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