[ricerice57]

hello guys, im new to site here .
im running a sub panel 80 ft. from main , am going to run 4 each #4 awg thhn wires and want to know if it is ok to run these in grey schedule 40plastic conduit, this will be inside the building up in the drop ceiling. also can i run this type of conduit inside the wall going down to the sub-panel?
thank you so much !

 

[AndrewF]

What is the type of wire you are running?

You can run a smaller ground wire than #4. I don't know which size is acceptable, someone else here will chime in.

Yes, you can use sCH PVC 40 that is rated for electrical.

 

[rgsgww]

What may the amperage be of the sub panel?

 

[Scuba_Dave]

How big is your main panel?
Have you done a whole house electric calc?
Not sure on #4 wire, I ran #6 for a 60a

How much power do you need?

 

[ricerice57]

main panel is 200 amp. I am planning on useing a 100 amp breaker to supply the sub panel and will have 8each 20 amp breakers in sub., at no time will there ever be all 8 circuits drawing full load at . worst case 24,000 watts divided among the 8 breakers no more

 

[ScottR]

Yes, the grey sch. 40 PVC is OK to use for the entire run.

#4 copper is OK for 100A, and you can use a #10 bare or green insulated wire for the ground.

worst case 24,000 watts divided among the 8 breakers no more

That's a full 100A @ 240V.. If you are planning on drawing more than 80A for more than 3 hours then you will have to up-size your wiring/panel. (Continuous loads are calculated at 125%).

Just curious, what are you running that's going to draw 24KW? (Or did you just mean "don't worry about it, I'm good"?)

 

[ricerice57]

we are running hair blowers on 4 rows of workstations i was calculating 16 hairblowers at 1500 watts each running all at the same time lol this will never happen in reality maybe 5 dryrers running at the same time and only for 5-10 mins each
thanks guys your really a big help :thumbsup:

 

[kbsparky]

#4 copper is OK for 100A, and you can use a #10 bare or green insulated wire for the ground....

Not quite. You will need to use #3 copper for the hot lines for a 100 Amp panel. The exception in section 310.15(B)(6) that allows one to use a #4 would not apply here.

Also, a #8 copper ground wire would be the minimum requirement.

In such a scenario, we would use (2)#3, (1)#4, and (1)#8 wires.

 

[ricerice57]

Thank you so much kbsparky this helps me out tremendously as i really want this to be a proffesional installation and in a case like this where money is tight what your telling me will save me quite a bit in contractor fees alone.
I love you guys , your all a great help and service to the community !:thumbup:

 

[Speedy Petey]

Not quite. You will need to use #3 copper for the hot lines for a 100 Amp panel. The exception in section 310.15(B)(6) that allows one to use a #4 would not apply here.

Not quite. In my area, and may others, we ARE allowed to use 310.15(B)(6) for feeders in a residence.


I have an issue here though.
Rice, you say: "we are running hair blowers on 4 rows of workstations".
Is this a commercial setting? If so many things change. The most important is that you likely should NOT be doing this work yourself unless you are licensed, insured and qualified to do so.

 

[ricerice57]

speedy pete I started to remove the old wires today and could not believe my eyes when i seen what a local licenced contractor did in up in the drop ceiling he took 6 circuits and ran them all to 1 4x4 box with 2 lines coming in each on a 20 amp breaker putting 3 lines to each breaker, all 6 of these circuits need to be on their own breaker. this guy really did a bad job and now i gotta fix his mess, no im not licenced but i have been in the industrial maint. industry for more than 20 years trouble shooting 460 3 phase 240 3 phase metal working machinery and food processing equipment. and i have built some very impressivemetal working equipment as well, so you see i am very knowlegable as far as running a simple sub-panel goes i just dont know the code as well as contractors do or supposed to know in this fools case.
thank you very much for your help and expertise in helping me out .:thumbsup: