Subpanel Disconnect at detached building.

[Will Wire]

The situation: Residential. I installed a 12/24 Load Center on a detached building. I am using a back fed breaker for the Disconnect. I also have Surge Protection. When I install the back fed disconnect breaker, I also loose the two spots horizontally next to it because of the hold-down bracket. When I installed Surge Protection, I lost two more breaker spots. In total I loose six one-inch Breaker spots.

Question: Is it NEC compliant to route the existing panel feed wires, through the existing load center in question, and mount a new Panel next to it to house the disconnect Breaker and the Surge Protection, then return from the disconnect back to the 12/24 load center. This would allow me to reclaim the 6 Breaker spots.

I am in the 2020 NEC.

Thank you,

Trent

 

[LarryFine]

Yes, although I would likely opt for a larger single panel. Tandems in this panel wouldn't be enough?

You could also leave the main and surge breakers in this panel and put your circuits in a sub-panel.

That way, you would only have to extend smaller wires to the sub-panel instead of the feeder itself.

 

[infinity]

Personally I would use a different panel. What panel needs 4 slots for a back-fed main CB?

 

[LarryFine]

Personally I would use a different panel. What panel needs 4 slots for a back-fed main CB?

Main and surge breakers. The main eats for spaces, the surge two.

That leaves 6/12 spaces/circuits, respectively.

Wait, is the surge in the breaker, or does it feed one?

 

[infinity]

Main and surge breakers. The main eats for spaces, the surge two.

Why does a 2-pole breaker require 4 spaces? There are panels that don't have that problem.

 

[Will Wire]

The panel is already installed. It is a Siemens SNW1224L1125. When you install the hold-down bracket for the back-fed breaker it won't allow breakers in the horizontal spaces next to it. I am considering changing the whole panel. I was looking for different NEC compliant options. I appreciate all the input.

 

[infinity]

The panel is already installed. It is a Siemens SNW1224L1125. When you install the hold-down bracket for the back-fed breaker it won't allow breakers in the horizontal spaces next to it.

That's a terrible design.

 

[LarryFine]

It seems that another 2p breaker would fit over the tab. If not, cut it.

 

[Will Wire]

It looks like it would. The one they are making now is a little different. I called Tech Support to see if I was doing something wrong. I was told no. The one I have, which is the accessory listed on the panel door does prevent breakers next to it. The new on has a larger protrusion and a screw.