[jmavris]

Indiana question:
I want to install a 60amp subpanel 150 feet from the main panel. This is all exposed runs both inside and out in a commercial envirenement.
What gauge and type of copper wire and what size conduit whould I use. How often should insert a junction box in the run.
John

[donf]

John,

Good morning. This site is set up for DIY users doing residential work. Not commercial installations.

Please contact several licensed electricians and get bids.

For example, if this were a residence, then you would use a #4/3 AWG copper with a 70 Amp breaker (sized for continuous use), 240/120 single phase connection.

However, I believe that Commercial uses three phase not single phase.

[maguyver]

6 gauge

[stanfortyman]

jmavris, if you have to come to a DIY message board to ask this question than obviously you are not qualified to do this work in a commercial environment.
Are you licensed to do this work? Obviously not. :mad:
Are you insured to do electrical work?? :rolleyes:

CALL AN ELECTRICAL CONTRACTOR to do this work, the a$$ you save could be your own.

[tkrussell]

Where is this requirement or limitation stated in this website?:

This site is set up for DIY users doing residential work. Not commercial installations.

While usually single family dwellings can be done by a homeowner, and everything beyond a this must be done by a qualified tradesman, I do not see why any question about anything other than a residential application is not allowed.

Please provide backup for your statement.

This is incorrect:

For example, if this were a residence, then you would use a #4/3 AWG copper with a 70 Amp breaker (sized for continuous use), 240/120 single phase connection.

Per NEC 2008 edition Table 310.15 (B) 6 - #4 copper can be used for a 100 amp residential feeder.


This statement illustrates some lack of knowledge and experience in the trade:

However, I believe that Commercial uses three phase not single phase.

Various two pole single phase electrical equipment, to include circuit breakers, panelboards, and disconnects are made up to 1200 amps single phase, and certainly are not limited to residential applications.

In an effort to answer the original question, while #6 copper is the minimum size conductor allowed for a 60 amp feeder, consideration must be taken for the load and distance. If the max load is 48 amps at 120 volts, the max wire size to allow for no more than 3 % voltage drop would be #3 copper wire.

This is a design issue, not a code issue, and a qualified electrician and/or engineer needs to be consulted to size this feeder.

[donf]

The answer, "This is for DIY residential" comes from past history on this forum.


I based my sizing on 240/120 vac, 150' length, continuous use (60 X 1.25% = 75 amp). Since the breaker will be carrying a constant load to the second building.

[donf]

Question, when sizing conductors for a 240/120 vac run, does the 120 vac take precedence over the 240 vac for calculation purposes?

[stanfortyman]

The 120 or 240v have NO bearing on wire size.

The only time they do is in figuring voltage drop, and we won't get into that now. TK and I strongly disagree on that subject. :p ;)

[mohdbg]

You can use 4c*16sq.mm cu /xlpe/swa cable in 50 mm dia.conduit with one pull box at 30 m.
Hope this will answer yor question.
Regards
Mohd

[stanfortyman]

Mohd, it is safe to say the OP is in North America and you are not, so your advice is not accurate for the situation.

Also, this thread is almost two years old. Please check the dates of the posts you are replying to.