sizing of service conductors

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Re: sizing of service conductors

How do you get away with having six meters feeding six different MDP's in various locations to comply with 230.72(A)? Do you call all six units separate structures?
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Not a problem if the basement is a common area and can be accessed by all tenants, and maybe even a good place to install a coin operated laundry?


Oh George I don't pick cotton. :D
 
Re: sizing of service conductors

Well, then, you don't have to wait. :D

Common basement. What will they think of next? :D

Just making sure I hadn't lost all my marbles. :D
 
Re: sizing of service conductors

Bob,
for argument's sake, does the MEC state a maximum length of service entrance conductor?

There appears to be a window directly below the meter to the far right. It has been argued by some that the loadcenter on the other end of the SEU could not be mounted at the 'closest point of entry'.
 
Re: sizing of service conductors

have read this and still puzzled ??
if you do not know load,and want to install a 200I 3 phase service would 4/0 AL be ok on 200 breaker? please be gentle Thanks GEO

[ May 23, 2005, 12:58 PM: Message edited by: vanwalker ]
 
Re: sizing of service conductors

If this is a 3? service, I assume it is not a dwelling unit and 250 kcmil Al. would be required since you can't use the 90?C ampacity. :D
 
Re: sizing of service conductors

THANKS CHARLIE i have been trying to explain to someone and they keep saying that it was ok , they are trying to be cheap, i told them they are incorrect with 4/0 al on commmerical.THANKS AGAIN
 
Re: sizing of service conductors

Truly, there's no good reason I can see for not being permitted to use that table for an apartment on a 120/208 system. Maybe someone will chime in with a good reason.

The reason you can't use the table is that you must adhere to every restriction laid out in that sub-section. It must be a "main SE or feeder" (whatever you interpret that to mean), 120/240, single phase, dwelling unit, etc. Not qualifying for one of the restrictions just means you miss the boat. :)
 
Re: sizing of service conductors

GEO's service is commercial, so forgetting about table 310.15(B)(6) I ask this.

If the calculated load were no greater than 180 amps, could we use 4/0 al and move up to the next size standard overcurrent device - 200 amp?
 
Re: sizing of service conductors

230.90(A) Ungrounded Conductor Such protection shall be provided by an overcurrent device in series with each ungrounded service conductor that has a rating or setting not higher than the allowable ampacity of the conductor.

Sorry Buck, no. 240.4(B) is not permitted to be used for a single service. :D
 
Re: sizing of service conductors

Thanks Charlie,
I should have this straight as one of my previous posts delt with this issue.
Just to make sure that I'm on the right track, using a similar example, 500 kcmil would not be permitted for a commercial 400 amp single service disconnect based on the same restrictions?
Thanks
Buck
 
Re: sizing of service conductors

230.90(A)Ungrounded Conductor

Exception No.2 Fuses and circuit breakers with a rating or seting that conforms with 240.4(B) or (C) and 240.6 shall be permitted

[ May 24, 2005, 06:47 PM: Message edited by: dillon3c ]
 
Re: sizing of service conductors

Originally posted by charlie:
Sorry Buck, no. 240.4(B) is not permitted to be used for a single service. :D
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Sorry Charlie I must disagree, 240.4(B) is often used on services, single or otherwise.
 
Re: sizing of service conductors

You know, sometimes you just have to read the exceptions. When you don't, you have to eat a little crow. Pass the salt please. :eek:
 
Re: sizing of service conductors

Originally posted by charlie:
you have to eat a little crow. Pass the salt please. :eek:
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Charlie,
Any member of this forum would testify to fact of the great advice and fine job, you perform in this forum sir..Most all of us would need to keep a paper-plate in pocket,and plastic fork behind our ear,in the performance of this job that you do..No man bats 1000% ...
 
Re: sizing of service conductors

now just one more question,if these conductors
3 phase 4 wire y. would they be required to be derate by having more than three current carrying in raceway. THANKS GEO
 
Re: sizing of service conductors

Generally speaking, neutrals don't count for current-carrying conductors unless the load is non-linear and has high harmonic content, but is still ocunted for conduit fill.
 
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