Service entrance conductor

[jjackson]

Can anybody tell me what the term kcmil means in terms of cable?

[Bob Badger]

KCMIL is a quantity of measure units; KCMIL is 1000 CMILS. All wire sizes larger than 4 ought AWG are given as KCMIL sizes. KCMIL wire size is the equivalent cross sectional area in thousands of circular mils. A circular MIL (CMIL) is the area of a circle with a diameter of one thousandth (0.001) of an inch, often termed CMA. Be aware that the wire sizes in the KCMIL system increase as the numbers get larger, which is exactly opposite from the AWG system.

[Erby Crofutt]

An excellent explantation, Bob.

When would I need this information.

[Paul W. Abernathy]

lol...If you do Residential Inspections....probably NEVER...lol

Online Definition...lol

Thousand Circular Mil; wire size for multiple stranded conductors over 4/0 AWG in diameter. Formerly MCM.

[Bob Badger]

Originally Posted by ecrofutt

An excellent explantation, Bob.

When would I need this information.

Thanks but I just grabbed it off the www.

You probably will not need that info.

4/0 takes us well into 200 amp services, above 200 amp services you might see conductors in kcmil

[Bruce A. King]

How much max current is acceptable for 500 kcmil underground service that runs 350 feet from the transformer to the meter ?

[Jeffrey R. Pope]

That would depend on the type (TW, UF, RHW, etc.) and material (AL or CU), but assuming there are not more than three current carrying conductors, the capacity can be from 260 amps to 430 amps (if I read the chart right).

[brian winkle]

Originally Posted by bking

How much max current is acceptable for 500 kcmil underground service that runs 350 feet from the transformer to the meter ?

As much as the POCO says. Utilities do not follow NEC standards.

[Paul W. Abernathy]

Great point brian.... In that question the answer lies in that the local UTL company chooses unless you are rural where they do not run the lines from the pad or pole to the house then the electrician would have to calculate it.

Funny how I have seen service drops that are HALF the size of the SE conductors from the meter to the panel and the UTL company never questions it so to be honest I never question it as it is not my business to question them.....I only get concerned on MY end of the equation.

Actually.....for math sake the amps on the 500KCMIL at 75 degrees is 380-400Amps in copper.

Jeff I think you used 60 degree factors in their, it is over 100A it needs to be at 75 degrees and can actually be used at the 90 degree if correction factors are going to be applied.

Anyway...assuming WE have to run the 500 KCMIL to a 400A service and they are using Copper....which happens alot.....

Ok.....at 400A going 350' and 500KCMil....the voltage drop would only by 3% and if using Alum you would have to adjust for it as well and increase wire size to account for it....Now this is RAW since nothing else has been figured in like correction factors for Temps.

I can say most of the runs for a properly placed PAD or POLE will not be 350'...but with all things said it is possible and in rural areas you have to consider it being a real possibility.

[Jeffrey R. Pope]

Originally Posted by pabernathy

Jeff I think you used 60 degree factors in their, it is over 100A it needs to be at 75 degrees and can actually be used at the 90 degree if correction factors are going to be applied.

Are you kidding Paul? Do you really think I did the math ?

I posted info directly from 310.16

[Paul W. Abernathy]

lol....I got ya brother.....Just use the 75 Degree and 90 Degree columns for the most part..unless you are having issues with terminal ratings that call for the 60 degree column to be used.

Most cases we use 75 degree unless a correction is needed then the 90 degree column can be used.

Your subtle point is also GREAT.....HI's generally dont need to worry about that....lol..You would HOPE the local AHJ checked that but heck in west virginia you never know...OH WAIT...I dont want to affend any West Virginians...Sorry Joe Ferry...tehehehhehehe

[Bruce A. King]

I was referring to AL in my prev. post

The temp. rating is unknown but with it underground I am not concerned with any heat rise for a residential application.

I'm not sure of the voltage at the transformer but its 120V at the panels with around 80 amps load.

[Paul W. Abernathy]

Originally Posted by bking

How much max current is acceptable for 500 kcmil underground service that runs 350 feet from the transformer to the meter ?

Dude.....are you SURE its 120V at the panel and 80A load....and they used 500 kcmil....?????

Now......those figures do not make any sense to me ( 500KcMil for those figures )..sorry I must be missing something here.

[Paul W. Abernathy]

I'm not sure of the voltage at the transformer but its 120V at the panels with around 80 amps load.

This is the part that is confusing.....your post for 500KCMil is certainly not going to be used in the above situation...

[Bruce A. King]

120V approx per leg and 80 amps per 120v leg under operation, max rating 400A via two 200A panels.

why was this hard to understand?
think residential homes...... were HI's