Ragamuffin

I am working on the design for an exisitng school built in 1960. A substantial addition was added in 1980. We will be replacing the panels, feeders and branch wiring in the 1960 portion. The 1980 addition, like the 1960 building does not have equipment grounding for feeders or branch circuits, the circuits appear to use the conduit as ground. I was planning to replace the panels and feeders to the 1980 addition to include a ground wire. Should I also call for the branch circuits to be replaced? What is the likelyhood that the existing conductors can be pulled out of the conduit and replaced with new conductors that include a ground in both the 1960 and the 1980 buildings? The panels feed receptacles, heating unit ventilators, exhaust fans, VAV terminals, AC equipment, etc.

480sparky

Require the circuits to be megged. Pulling circuits out and repulling with EGCs may create fill issues.

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In winter, why do we try to keep the house as warm as it was in summer when we complained about the heat?

Dennis Alwon

The conduit , assuming metal is perfectly legit as an equipment grounding conductor (EGC). If the conduit is indoors there is a pretty good chance wires can be replaced quite easily but maybe unnecessarily.

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Cletis

You have a good chance of doing all that. Those old time electricians did really good work. That's back when there was alot of pride in the work and before craigslist. Hopefully, they didn't pack the conduit too much for your egc's

Ragamuffin

Ok. If the Megger test passes, the conductors remain and get connected to the new circuit breakers. If the Megger test fails, the conductors get replaced with new to include a grounding conductor.

Ragamuffin

Looks like I will have to have a lot of CYAs on the drawings. Such as perform a Megger test, if it fails, pull new conductors with ground; if the conduit fill exceeds NEC fill capacity, install conductors in new conduit. That is an estimating nightmare...

Dennis Alwon

If you are going to make them pull an egc then it is probably not worth megging the circuits. I would just say replace all wiring. If you are okay with the conduit as the egc (perfectly compliant) then I would have a separate price with megging and not replacing wires if they pass.

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480sparky

Again, it may create a fill issue. How does one bid for that?

If I saw something like that in the specs, I'd either bid it to repipe & rewire everything, or not bid at all.

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In winter, why do we try to keep the house as warm as it was in summer when we complained about the heat?

nitro71

Are you talking about megging and replacing the conductors in the 1980's structure or those in the 1960's structure?

Shockdoc

Why would you even consider running a ground wire if it's all run in rigid and EMT ? that's just a complete waste of time, material and resources. I would install new grounding devices with self grounding clips and /or run a ground pigtail from box to device. I'm sure there is a solid ground with that system.

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All these liberal laws has turned me into a right wingnut..

BBQ

I have the same question.

Ragamuffin

Would the wiring installed in the 1960s be good for another 40-50 years? I am trying to find a sensible solution so that I am not killed by change orders when the panels are changed over because the grounding is no good. At the same time I do not want to waste resources if the system will be good for another 40-50 years.