Need to add Critical Load Panel

[Supervstech]

This is another reason why I prefer my panels accessible in an unfinished part of the basement and not in a finished wall. I can actually work on it!
I put my critical loads panel near my main, with a 2" EMT conduit running between them. I'm leaving all the existing circuit grounds and neutrals where they are in the main, and simply moving the hots and breakers of the circuits I want through the EMT to the critical loads panel.

It kinda sucked having to buy a 10' length of 2" conduit so I could cut off 18 inches of it, but ya know...

Many electrical supply houses offer scrap chunks of conduit free, or a minimal charge.

 

[SparkyJJO]

Many electrical supply houses offer scrap chunks of conduit free, or a minimal charge.

Wish I had known and or thought of that.

 

[HighTechLab]

@HighTechLab, looks like you just had a ground bar in the trough for all the Romex runs and a single run down to panel. Inspector did't have an issue with that?

Not a problem. Bonded is bonded. We do this all the time on commercial projects with MC cable. I used 6AWG to tie in the inverter, main panel, etc.

I did have to go back and swap out some breakers for AFCI/GFCI's because touching the old work meant that now I needed to bring it up to the latest standards.

My bigger worry was the number of current carrying conductors going through the flex, because it was ever so slightly longer than the maximum distance you can run without derating...but I got away with it. The limit is 24 inches before you have to derate for more than 3 current carrying conductors.

I'm leaving all the existing circuit grounds and neutrals where they are in the main, and simply moving the hots and breakers of the circuits I want through the EMT to the critical loads panel.

I don't think this is legit. There is a safety issue to someone working on the main panel. One can lock out the power source for the panel, check for voltage and find none, and then lift that neutral and get bit. The wire that you "know" is dead bites the hardest.

I'll try and reference NEC 210.4(A) and 300.3(B)

 

[SparkyJJO]

I don't think this is legit. There is a safety issue to someone working on the main panel. One can lock out the power source for the panel, check for voltage and find none, and then lift that neutral and get bit. The wire that you "know" is dead bites the hardest.

I'll try and reference 210.4 Multiwire branch circuits
(A)General.
...All conductors shall originate from the same panelboard or similar distribution equipment.

I didn't think of it that way at all. Just fewer connections to make and extend (and thus costs less too).

Learned something new!

 

[ChrisG]

My bigger worry was the number of current carrying conductors going through the flex, because it was ever so slightly longer than the maximum distance you can run without derating...but I got away with it. The limit is 24 inches before you have to derate for more than 3 current carrying conductors.

@HighTechLab Do you happen to have the NEC code reference for this. I'll probably have 10 runs of 12/2 swinging over as well as the feeder, probably more than 24" based on panel placement. Is it: Table 310.15(B)(3)(a)

 

[Supervstech]

@HighTechLab Do you happen to have the NEC code reference for this. I'll probably have 10 runs of 12/2 swinging over as well as the feeder, probably more than 24" based on panel placement. Is it: Table 310.15(B)(3)(a)

Think about it like this...

How are gfci or afci interrupts supposed to work without a neutral to feed?

 

[ChrisG]

Think about it like this...

How are gfci or afci interrupts supposed to work without a neutral to feed?

I plan on extending hot and neutrals for each circuit. Leverage busbar like Dexter did for ground. Reading further about derating:

• If more than 3 current carrying conductors in more than 24" of conduit, need to derate
• If using a METAL gutter/trough, need to derate AFTER more than 30 current carrying conductors

Moving 10 circuits from current panel, through gutter, extending circuits up 20" of conduit to new sub panel, I don't need to derate at all.

Sound correct?

 

[HighTechLab]

I plan on extending hot and neutrals for each circuit. Leverage busbar like Dexter did for ground. Reading further about derating:

• If more than 3 current carrying conductors in more than 24" of conduit, need to derate
• If using a METAL gutter/trough, need to derate AFTER more than 30 current carrying conductors

Moving 10 circuits from current panel, through gutter, extending circuits up 20" of conduit to new sub panel, I don't need to derate at all.

Sound correct?

Sounds good. On the gutter 30 conductor part, this is in one cross-section. So, in other words, if you had 20 circuits in the middle = 40 current carrying conductors, if you had half going to a nipple on the left and the other half going to a nipple on the right, no cross section has more than 30, so you are fine.

 

[ChrisG]

Sounds good. On the gutter 30 conductor part, this is in one cross-section. So, in other words, if you had 20 circuits in the middle = 40 current carrying conductors, if you had half going to a nipple on the left and the other half going to a nipple on the right, no cross section has more than 30, so you are fine.

Thanks @HighTechLab . This house is 25 years old and panel never touched so by extending to sub, now need to look across all circuits and figure out which ones need gfci and/or arc fault. Ugh.

 

[SparkyJJO]

Thanks @HighTechLab . This house is 25 years old and panel never touched so by extending to sub, now need to look across all circuits and figure out which ones need gfci and/or arch fault. Ugh.

I'm just moving my existing breakers to a matching panel, not upgrading to AFCI anything. Shhh..... No permits pulled here

 

[ChrisG]

Sounds good. On the gutter 30 conductor part, this is in one cross-section. So, in other words, if you had 20 circuits in the middle = 40 current carrying conductors, if you had half going to a nipple on the left and the other half going to a nipple on the right, no cross section has more than 30, so you are fine.

Getting ready to do this work and rethinking use of gutter. Neutrals are also current carrying conductors. Moving 10 circuited will be 20 conductors between old and new panel.

Think I may just nipple the recessed panels together and call it a day. Will ‘plumb’ for new AC OUT of main panel to inverter and a AC IN from inverter to sub panel. The manual transfer switch will be fully removed from solution.

Recessed panels are a pain in the ass.