"Older" Panelboards

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Ragin Cajun

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Upstate S.C.
I just started a large project where we are upgrading the electrical in three two and three story classroom buildings that are 40+ years old.

Replacing/relocating the main service panelboards is a given. Ditto for the feeders to the sub panels. (That will be fun for the electrician!)

I have a question regarding these sub panels. They are all Square D, in excellent shape, and lightly loaded. They look good.

My question is two fold. I can replace the entire interior (bus and breakers), or possibly only the breakers. All the panels are NQOD using standard QO breakers. Voltage is 120/208V. With few exceptions, the panels are 225A MLO.

I look at the panel interior (bus) and everyone looks fine. No evidence of overheating, burned out breakers, etc. I see saving the owner serious money and down time by replacing only the breakers, yet giving him essentially new interiors. The bus is "metal" so there is nothing to really deteriorate. All panels are in conditioned spaces.

As for the various branch circuits, I don't see enough $$ in the budget to replace this wiring and it would be difficult with everything concealed, possibly hidden, buried JB's, etc. The branch wiring looks good. I might have as an additive alternate to replace the receptacles and light switches.

Anybody run into this before?? Suggestions?

Thanks ahead of time!

RC
 
Agreed. Unless they specify new equipment, I see no reason to replace even the breakers.
 
Thanks for the replies.

The client has money to replace all panelboards. As the building is over 40 years old, they want to use the buildings for many more years. They would like to replace all wiring, but that kind of money isn't there and I just don't see replacing the branch wiring.

I really don't see leaving 40 year old breakers in at this point. As was mentioned, they are not expensive. Even though most have never been used, that may be an issue by itself. Has the lubricant dried out and will they trip?

I guess that brings up another good question. What IS the reasonable expected lifetime of a QO breaker, or any other similar breaker??


I want to give the client the best bang for the buck to give the electricdal systems many more years of use.

Thanks,

RC
 
Circuit breakers 40+ years old are an inigma. You or anyone else cannot tell what the condition of any one of them is without testing.

You mention that there is money in the budget or the budget was set with the thought of changing the panels/CBers. Change the panels and circuit breakers.

The condition of the branch circuit/feeder conductors is an unknown. Those conductors have been in place for 40+ years. There is a way, as Zog mentioned, to get a better idea of the condition of those conductors, and that is to megger them. Visually looking at conductors is not the way to decide if those old conductors are in good shape. Remember, the older conductors were designed with a 50 year life span.



You also mention the customer wants to use the building for many more years to come. Perform as much new work as is financially possible and then set a plan in place to replace other old wiring/work as is possible in the future - that is called good marketing for your business and good service for your customer.
 
Ragin Cajun said:
The client has money to replace all panelboards. As the building is over 40 years old, they want to use the buildings for many more years. They would like to replace all wiring, but that kind of money isn't there and I just don't see replacing the branch wiring.
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In that case, I do agree with leaving the enclosures and replacing only the guts. Replacing the enclosures would be hard on the existing conductors, as well as the building itself.
 
Ragin Cajun said:
…I guess that brings up another good question. What IS the reasonable expected lifetime of a QO breaker, or any other similar breaker??


I want to give the client the best bang for the buck to give the electricdal systems many more years of use…
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Breaker warrantee is stipulated per manufacture. Breakers could last many years but only if they have not tripped, if they have tripped (including the likelihood of tripping) they may not even be an OCPD any longer. This is probably the best point to make to your client.

The only true proof of a breaker is a commissioning test, otherwise if your professional opinion is to replace them do so. This will “restart collectively”, so to speak, the OCP needed/required per circuit.
 
tryinghard said:
Breaker warrantee is stipulated per manufacture. Breakers could last many years but only if they have not tripped, if they have tripped (including the likelihood of tripping) they may not even be an OCPD any longer.
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The only issue with breakers is when they have interrupted a fault at or near their maximum AIC rating. For branch circuit molded case breakers, normal overload current (up to maybe 6x FLA) would not concern me.
 
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