Multiple wires into a panel

[jjhoward]

Hello All,
I've got a residence with a basement remodel.
4-15 amp 120V circuits (2 split circuits)
1-15 amp 240V circuit
1 20 amp 120V circuit
Looking to run THHN in 3/4" sch40 from the basement area to the breaker panel in the garage. Can I run the conduit right to the panel and bring in the 10 current carrying conductors through the single KO or must I seperate the conductors into their circuits prior to entering the panel??

Thank you.

 

[RUWired]

Re: Multiple wires into a panel

Joe ,If you are going to run conduit with single conductors,you must run this conduit and conductors directly into the panel with approved and listed fittings,on both ends of the run.However with this amount of current carrying conductors, you must use the adjusting factors tables of 310.15(B)(2)a. With 10, you must use the 50% value.What this means is,you will need to up size all your 14awg to 12awg, your 12awg to 10awg.It will still fit in a 3/4 pvc conduit,but the box in the basement will need to be a minimum of 46 cu ".and a rats nest if you don't fold your wires properly.
Rick

 

[Brian M]

Re: Multiple wires into a panel

They can all enter the panel together, through the required bushing on the connector on the end of the conduit. Your question is puzzling, and I'm thinking that you don't run much conduit. But why would you think that the individual circuits might have to enter the panel in seperate conduits when they are allowed to be run together in the same conduit?

 

[Brian M]

Re: Multiple wires into a panel

RUWired, there are only 8 countable conductors in that run, so they aren't required to be derated at 50%. The 2 neutrals of the 2 15A 3-wire multiwire (JJ referred to as "split") circuits are not counted - assuming that this is not a 3-phase supply.

 

[throttlebody]

Re: Multiple wires into a panel

Originally posted by Brian M:
They can all enter the panel together, through the required bushing on the connector on the end of the conduit.

Wouldn't 300.4(F) allow him to not use a bushing since he has no conductors 4AWG or larger, according to the footnote in 352.46? I don't have a 2005 handy, but am referencing 2002.

 

[jjhoward]

Re: Multiple wires into a panel

Hi Brian,
Yes, I don't run much conduit. Just not sure if there was some limit on the number of single conductors that can be brought into a panel via a single opening.

I will review the derating issue. Bumping the 14's to 12 is OK, bumping up the 12's to 10 will be a pain.

 

[jjhoward]

Re: Multiple wires into a panel

Can I not count the neutral of the split circuits as current carrying??
There will only be 2 of the 3 conductors in the split circuit carrying current. So...looks like I will have 8 current carrying conductors-- 70% derating.
I still may need to up the size of my wires.
Thank you all!!

 

[Brian M]

Re: Multiple wires into a panel

Wouldn't 300.4(F) allow him to not use a bushing since he has no conductors 4AWG or larger, according to the footnote in 352.46? I don't have a 2005 handy, but am referencing 2002.

352.46 requires protection from abrasion of ALL conductors in the fitting regardless of size - but not necessarily insulated protection. The footnote references 300.4(F) for #4 or larger conductors to be provided with insulated protection - regardless of conduit type used.

You'll find the same footnote after 344.46 requiring abrasion protection for the raw ends of RMC, and even 362.46 for smurf tube.

 

[infinity]

Re: Multiple wires into a panel

The conduit would contain 8 CCC's. Using #12 THHN would be fine.

#12 THHN-(30 amps)(70%)= 21 amps max OCPD, or you could use
#14 for the 15 amp circuits and #12 for the 20 amp.

#14 THHN-(25 amps)(70%)= 17.5 amps max OCPD.

 

[RUWired]

Re: Multiple wires into a panel

Yes ,i was thinking it counted ,but after reading, it is only in 3-wire circuits of 3 phase systemsRick

 

[throttlebody]

Re: Multiple wires into a panel

Thanks Brian, I was overlooking the "insulated" word.

Hee hee, smurf tube. That is the common term for it here. Some started using the grey ENT and were calling it smurf tube. I said, "wait now, smurfs are blue, you'll need another character for the grey".