I have often heard that aluminum wire is unsafe and copper is a better choice. Now I’m in the process of finishing a new power pole install and found my local utility company (PG&E) requires aluminum wire from the service head to the meter. What is the story with aluminum vs copper wire? If copper is a superior wire why would they require aluminum?
Image shows PG&E residential wire requirements.
Replies
There were problems with solid aluminum branch circuit wires used in the 70s; different situation entirely from stranded aluminum service line wires.
Do they realy ALLOW ONLY aluminum or is that all that is given as that is what is almostly always used?
I have an inspection tomorrow so I'll see what PG&E says about the copper.
I had already installed copper in the conduit prior to finding out about the aluminum, what a bummer! Hopefully the copper is ok to use.
I'll let you know what they say.
Yeah, service lines could be copper but they never are. Large gauge copper is very hard to find. As long as you (or PG&E) puts the anti-corrosion goo on the connections, aluminum service wiring is fine.
Up here in L.A., the DWP wants you to give them 3' of copper hanging out of the weatherhead, and they splice to that using their aluminum. For big expensive feeders, it's worth going to the extra effort of making good aluminum terminations, but for branch circuits it doesn't make sense.
-- J.S.
Hmm. That's a new one on me. The only thing that comes to mind is that copper exposed to weather forms oxides that partially dissolve in water, as free ions I understand, and this solution can corrode aluminum over time. Aluminum does not form a corrosive solution. The rate of deterioration isn't very fast and often doesn't show up at all.
The solution around here is to make sure the aluminum is located above the copper so that any rain water that has been exposed to the copper does not then fall on the aluminum. I know of no local or NEC requirement on this but in this area it is a generally accepted practice.
Seeing as that the utility company uses aluminum, for weight and cost savings, using aluminum in the riser would eliminate the possibility altogether.
Here is the latest, PG&E did their inspection today and made no mention of my copper wire. I think PG&E is mainly interest in the pole but he looked it over pretty well and just told me to move over my TV and telephone conduit. Tomorrow is the county inspection so I’ll see what they say.
In Code Check Electrical I noted that they rate 0/1 Aluminum and #2 copper the same so I guess the load capacity is arguably equivalent.
Inspection conclusion
The county came out and inspected the new power pole, main & sub panel and wiring. The job passed inspection and the inspector never mentioned anything about the type of wire used.
I guess PG&E has just listed the bare minimum for wire and possible didn't bother to include copper in their green book?