Three story dwelling unit

Ponchik

Ponchik

Senior Member
Location
CA
Occupation
Electronologist
Based on 215.18 (2023NEC)

A three story single family dwelling with one sub panel at each floor, needs one 10KA rated SPD for each sub panel.

Am I interpreting that correctly?
 
The sub panels don't need a main breaker in them. The breaker at the main panel, where they are fed, is all that is needed
 
Ponchik said:
Based on 215.18 (2023NEC)

A three story single family dwelling with one sub panel at each floor, needs one 10KA rated SPD for each sub panel.

Am I interpreting that correctly?
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If I'm reading 215.18 correctly, yes.
 
I know some bay area inspectors are saying once CA starts using the 2023 NEC they are going to require all panels to have SPD's

215.18 states that feeders that supply dwelling units require SPD's. It doesn't say that all feeders supplying loads in dwelling units. To me if a feeder is supplying a dwelling it must meet the definition of a dwelling.

3 bedrooms and 2 bathrooms is not a dwelling unit.
A kitchen, family room, bathroom and foyer is not a dwelling unit.
A garage and laundry room is not a dwelling unit.
 
My response up above was not pertinent to the question. Sorry, I read it wrong. Imo, the code states that a spd must be connected to the load side of a feeder that serves other breakers. However, there should be an "and" in there. I am curious as to what they really want. I don't see how you can install it in a MPD and be connected to the load side of feeders. My guess it is required in all panels.

(B) Location.

The SPD shall be installed in or adjacent to distribution equipment, connected to the load side of the feeder, that contains branch circuit overcurrent protective device(s) that supply the locations specified in 215.18(A).
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jaggedben said:
On a single family dwelling unit if there is an SPD at the service then none are required at subpanels. Number of stories is irrelevant.
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I would think that were the case but I'm having a difficult time finding supporting Code language in Art 215 or 242. Can you enlighten me.
 
augie47 said:
I would think that were the case but I'm having a difficult time finding supporting Code language in Art 215 or 242. Can you enlighten me.
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See what curt said. In my opinion a feeder only supplies a dwelling unit if it serves all the elements of a dwelling unit. If a subpanel is just for a kitchen that's not a dwelling unit. If it's just for upper floor bedrooms and bathrooms that's not a dwelling unit (although if there's a closet then I guess it meets the definition of a guest suite? 🤔) If the bottom floor is just the garage and storage that's definitely not one of those occupancies. Not like a service panel or an MDP sub that serves the entire unit.

If you do put SPDs in all the subs then you shouldn't need one at the service panel. (See 230.67(B) exception.)

I mean I get that the CMP is pushing for more SPDs near the load but they weren't too explicit and I hope AHJs will use their judgment. I guess when 2023 comes around here next month I'd be making sure my panels have space for them but not putting them in until asked.
 
jaggedben said:
See what curt said. In my opinion a feeder only supplies a dwelling unit if it serves all the elements of a dwelling unit.
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And one of those element is being "complete and independent". So even if, e.g. the 3rd floor feeder supplies a bedroom, bathroom, and satellite kitchenette, unless the 3rd floor can be closed off from the rest of the building and accessed independently, it would not be a dwelling unit.

Cheers, Wayne
 
jaggedben said:
See what curt said. In my opinion a feeder only supplies a dwelling unit if it serves all the elements of a dwelling unit. If a subpanel is just for a kitchen that's not a dwelling unit. If it's just for upper floor bedrooms and bathrooms that's not a dwelling unit (although if there's a closet then I guess it meets the definition of a guest suite? 🤔) If the bottom floor is just the garage and storage that's definitely not one of those occupancies. Not like a service panel or an MDP sub that serves the entire unit.

If you do put SPDs in all the subs then you shouldn't need one at the service panel. (See 230.67(B) exception.)

I mean I get that the CMP is pushing for more SPDs near the load but they weren't too explicit and I hope AHJs will use their judgment. I guess when 2023 comes around here next month I'd be making sure my panels have space for them but not putting them in until asked.
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In California, make sure you keep a double space open in the main panel, for future solar.
 
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