408.35 Number of Overcurrent devices on one panelboard

[davedottcom]

Need to add a (2-pole) surge protector in a 40-space panel that is Full.

Installing(2) tandem breakers and the Surge protector shouldn't be a violation since there is still only 40 over current devices.

A surge protector isn't an over current device it's an over Voltage device!!!

Right!?

 

[jaggedben]

The breaker for the surge protector is an overcurrent device.

 

[davedottcom]

The surge protector is the "Plug-in" style and doesn't require a circuit breaker.

 

[MAC702]

I agree with the OP. The question is who else is going to look at it and approve it? Will tandems work in the panel?

 

[davedottcom]

I agree with the OP. The question is who else is going to look at it and approve it? Will tandems work in the panel?

If (2) Non-Circuit-Limiting Tandem breakers are installed there will still be only 40 over current devices and (1) 2-pole Surge protector.

 

[MAC702]

If (2) Non-Circuit-Limiting Tandem breakers are installed there will still be only 40 over current devices and (1) 2-pole Surge protector.

I must admit I don't know how that answered or addressed my questions.

 

[davedottcom]

I must admit I don't know how that answered or addressed my questions.

Well, it's a Sq-D QO panel so yes it definitely accepts NCL-tandem breakers. The reason the panel will be completely FULL is; I'm installing the 40th circuit! Yes, there will be an inspection but I'm not just trying to get it to "pass inspection", I'm trying to find out if it's "NEC compliant". 2 Very different things!

 

[davedottcom]

The reason the panel will be completely FULL is; I'm installing the 40th circuit!

Correction! I'm installing the 39th circuit, not the 40th. Currently there are 38 circuits/spaces used in a 40 space panel. I'm adding 1 more single pole and the surge protector requires 2 spaces although it's not an over current device.

 

[infinity]

I'm confused how many spaces does the panel have?

 

[davedottcom]

I'm confused how many spaces does the panel have?

lol... ok...

It's a 40 space / 40 circuit QO panel
It currently has 38 spaces used (Circuit breakers)
That leaves 2 spaces for the surge protector
The surge protector is not an over current device so there is still only 38 circuits but no more room for the 39th circuit.
I want to replace 1 single pole breaker with a NCL QO tandem for the 39th circuit.
Technically, I could do this again for a 40th circuit someday and there would still only be 40 over current devices and a 2-pole surge protector.

 

[tom baker]

Panelboards are no longer limited to 40 devices, that requirement was changed many code cycles ago

 

[infinity]

lol... ok...

It's a 40 space / 40 circuit QO panel
It currently has 38 spaces used (Circuit breakers)
That leaves 2 spaces for the surge protector
The surge protector is not an over current device so there is still only 38 circuits but no more room for the 39th circuit.
I want to replace 1 single pole breaker with a NCL QO tandem for the 39th circuit.
Technically, I could do this again for a 40th circuit someday and there would still only be 40 over current devices and a 2-pole surge protector.

The number of OCPD's is irrelevant, the issue may be that the panel is not listed for use with tandem circuit breakers.

 

[davedottcom]

Panelboards are no longer limited to 40 devices, that requirement was changed many code cycles ago

I just realized I was using my 2005 NEC! :roll:

 

[davedottcom]

The number of OCPD's is irrelevant, the issue may be that the panel is not listed for use with tandem circuit breakers.

Ahhh... well, that would change things!

If that's the case, No Surge protection for them!

 

[MAC702]

Ahhh... well, that would change things!

Which would be why I asked.

 

[Buck Parrish]

Chances are some of the circuits may only have one outlet on it. Or perhaps a light or two maybe a door bell transformer. You can pig tail those in the panel to make an extra space or two.

 

[davedottcom]

Chances are some of the circuits may only have one outlet on it. Or perhaps a light or two maybe a door bell transformer. You can pig tail those in the panel to make an extra space or two.

Yes very true.

Ok... I'm going to say something I'm probably going to regret but... aren't Square-D breakers permitted to have 2-wires on their terminals? 1 on each side of the screw. (They sure look like they are!)

 

[LarryFine]

Yep. Them and CH (et al) for 14, 12, and 10 wire.

 

[MAC702]

Ok... I'm going to say something I'm probably going to regret but... aren't Square-D breakers permitted to have 2-wires on their terminals? 1 on each side of the screw. (They sure look like they are!)

Depends on if you are asking Square D, the NEC, the AHJ, a real electrician (all of whom say yes), or a Home Inspector.

 

[kwired]

The number of OCPD's is irrelevant, the issue may be that the panel is not listed for use with tandem circuit breakers.

+1

Yes very true.

Ok... I'm going to say something I'm probably going to regret but... aren't Square-D breakers permitted to have 2-wires on their terminals? 1 on each side of the screw. (They sure look like they are!)

typical 30 amp and less are designed to accept two conductors on their terminals.

Depends on if you are asking Square D, the NEC, the AHJ, a real electrician (all of whom say yes), or a Home Inspector.

HI's can't seem to figure this one out.