Transfer Switch/sub Panel

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  #1  
Old 07-05-08, 09:24 PM
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Transfer Switch/sub Panel

Hello all,

I'm about to begin installing a Reliance Controls TRC0603A Transfer Switch. I have three small questions. This switch/sub panel has a 60amp utility capacity and 30amp generator capacity.

1) Is 6 awg wire adequate?

2) Should I use individual wires or buy a few feet of 6/3 cable? Maybe SER cable?

3) Does this wire need to be in a conduit from the switch to the panel? They will be side by side and all of the wiring will be concealed in wall.

This will be inspected, so I'm looking to be code compliant.

Thanks
Gary
 

Last edited by zoom38; 07-05-08 at 09:47 PM.
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Old 07-05-08, 09:59 PM
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#6 Wire is fine

I would use conduit but not required, if using Romex (SER not needed) it must concealed in wall or protected. I strongly recommend conduit for the branch circuits so that you can add remove wiring in future without much hassle.

also most inspectors will require you to bring the individual circuit neutrals into new panel, not just the hots
 
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Old 07-05-08, 10:23 PM
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Originally Posted by rich3236 View Post

Also most inspectors will require you to bring the individual circuit neutrals into new panel, not just the hots

This part is pretty critcal due most inspectors will nail on this one and I did see few transfer case failure due poor setup with netural not moved to the generator subpanel especally that is true if you have GFCI breaker or AFCI breaker.

Merci,Marc
 
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Old 07-06-08, 07:02 AM
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Thanks gents,

This if a relatively new install, i'm doing a second floor addition with new service panel. Because of this I will be bringing only the necessary circuits directly into the transfer switch so I will be avoiding splicing them in the service panel and all neutrals will be in there.

If I understood you correctly I don't need to use conduit with NM or SER cable but in case I use individual wires is conduit required? Again they will be concealed in wall when complete.

I just found info on NM and SER cable on Southwires site. It states that "NM-B cable may be used for both exposed and concealed work in normally dry locations at temperatures not to exceed 90 deg. celcius (with ampacity limited to that for 60 deg. celcius conductors) as specified in the NEC." Then looking at their table, it seems that 6awg NM cable is only good up to 55 amps.

In looking at their info on SER cable it states
"60C - When terminated to equipment for circuits rated 100 amperes or less or marked for 14 through 1 AWG conductors.
75 C - When terminated to equipment for circuits rated over 100 amperes or marked for conductors larger than 1 AWG.
90C - Wet or dry locations. For ampacity derating purposes"

According to the above I interpret it that I need to use the 60 deg c rating and 6-6-6-6 cable is rated for 55 amps also.
I interpret all this that for 60 amps I need to go up to 4 awg NM or SER cable. Am I correct or am I missing something.


Thanks Again
Gary
 

Last edited by zoom38; 07-06-08 at 08:42 AM.
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Old 07-06-08, 10:09 PM
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According to the above I interpret it that I need to use the 60 deg c rating and 6-6-6-6 cable is rated for 55 amps also.
I interpret all this that for 60 amps I need to go up to 4 awg NM or SER cable
It depending on if you used copper or alum verison the ampacapity will varies a bit normally copper can use more ampcapitcy than alum verison

6-6-6-6 Alum is only good for 50 amp while the 6-6-6-6 Cu SER is good for 60 amp [ there is few on market but 6-3W/G NM copper is the same rating also ]

Yeah there is 55 amp fuse but not very often used so with alum I rather down size a bit for safety reason to 50 amp.

The 50 is very common as 60 amp as well you can find them very easy in big box stores but just watchout on the wire itself it can change the rating pretty fast.

Merci,Marc
 
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Old 07-06-08, 11:08 PM
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Originally Posted by zoom38 View Post
If I understood you correctly I don't need to use conduit with NM or SER cable but in case I use individual wires is conduit required?
You understand correctly.

it seems that 6awg NM cable is only good up to 55 amps.
That is correct, however the code allows you to round up to the next standard breaker size, in this case 60A, when the calculated wire ampacity falls between breaker sizes. Therefore, the #6 copper NM is just fine for a 60A subpanel.
 
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Old 07-07-08, 11:33 AM
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Thanks for the input.

Gary
 
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