Federal Pacific electrical panel

[Andres Arias]

Hi everybody. What is the main reason which the Federal Pacific brand electrical panels must be replaced prior to the installation of a PV system in the Point of interconnection?

Thanks

 

[augie47]

There are valid safety reasons for replacing a FPE "Stab-Lok" panel in any situation although doing so it not required by the NEC.
Some insurance underwriters ask that they be replaced (and perhaps some local jurisdiction)

 

[Fred B]

Likelihood of meeting this requirement highly unlikely with the FPE Stab-Lok panel.
705.12(B)(3)(3)
The sum of the ampere ratings of all overcurrent devices on panelboards, both load and supply devices, excluding the rating of the overcurrent device protecting the busbar, shall not exceed the ampacity of the busbar. The rating of the overcurrent device protecting the busbar shall not exceed the rating of the busbar.

This section looks to assume the potential that every circuit will be on and operating at full capacity, and if the addition of the PV into the panel would overload the bus. FPE has a dubious history with overload and heating causing fire, thus recommendation is normally to upgrade whenever installing anything that would increase the loads on the panel bus.
Potentially use of supply side tap for interconnection of the PV could circumvent the "need" to replace a FPE panel, but replacement of a potentially inherently unsafe panel that has known safety concerns would be advisable regardless of interconnection design.

 

[xformer]

Likelihood of meeting this requirement highly unlikely with the FPE Stab-Lok panel.
705.12(B)(3)(3)
The sum of the ampere ratings of all overcurrent devices on panelboards, both load and supply devices, excluding the rating of the overcurrent device protecting the busbar, shall not exceed the ampacity of the busbar. The rating of the overcurrent device protecting the busbar shall not exceed the rating of the busbar.

This section looks to assume the potential that every circuit will be on and operating at full capacity, and if the addition of the PV into the panel would overload the bus. FPE has a dubious history with overload and heating causing fire, thus recommendation is normally to upgrade whenever installing anything that would increase the loads on the panel bus.
Potentially use of supply side tap for interconnection of the PV could circumvent the "need" to replace a FPE panel, but replacement of a potentially inherently unsafe panel that has known safety concerns would be advisable regardless of interconnection design.

Whats the substantiation for that?

 

[rc/retired]

There are valid safety reasons for replacing a FPE "Stab-Lok" panel in any situation although doing so it not required by the NEC.
Some insurance underwriters ask that they be replaced (and perhaps some local jurisdiction)

Correct. One year I had bunch of panel replacement inspections. They were all driven by insurance.
Apparently they told their clients they would not insure them if they had FPE oe Zinsco.

Ron

 

[jaggedben]

Hi everybody. What is the main reason which the Federal Pacific brand electrical panels must be replaced prior to the installation of a PV system in the Point of interconnection?

Thanks

Same as I just posted in your other thread, there is no reason that PV systems in particular should trigger replacement. There are legitimate reasons to avoid working on FPE panels or adding circuits, but they apply to any electrical work as much as they do to adding PV.

Also the mere presence of a PV system on a site means nothing. For example, in the case of a downstream FPE subpanel where a PV system was added to the main panel upstream, it makes no difference to the subpanel and the decision to replace the sub (while arguably prudent) is totally separate.

 

[jaggedben]

Likelihood of meeting this requirement highly unlikely with the FPE Stab-Lok panel.
705.12(B)(3)(3)
The sum of the ampere ratings of all overcurrent devices on panelboards, both load and supply devices, excluding the rating of the overcurrent device protecting the busbar, shall not exceed the ampacity of the busbar. The rating of the overcurrent device protecting the busbar shall not exceed the rating of the busbar.

That isn't a requirement on all PV installations, it's an option for compliance among others. And it's no more or less likely to be met in an FPE panel than others.

On a similar note, however, the more commonly used '120% rule' (which comes right before the one you quoted in the book) requires the PV breaker to be at the opposite end of the panel from the main breaker. Some FPE panels have the two hot legs fed from opposite ends, so this isn't possible. (Some other brands have this too, but it's common on FPE.)

I do not believe there is any reason to suspect that the 120% rule is otherwise more dangerous on FPE than other panels.

 

[hillbilly1]

The biggest problem I’ve seen with FPE, is not the buss, but the ocp. I think they are thermal trip only, not thermal/magnetic. Hard to trip one, and if you do, the wire is probably already damaged. I’ve had the same issue with the bolt-in FPE breakers as have the plug on.