Another Al Wiring Question

[wvaidic]

Is Aluminum wiring for the service entrance wires okay? I believe only single strand aluminum branch wiring is a problem, but want to confirm.
Thanks

[Stephen W. Stanczyk]

Not a problem. I would bet that 95% of the homes I inspect are aluminum. Copper is a rarity.

[James R. Szczesny]

Not a problem. I would bet that 95% of the homes I inspect are aluminum. Copper is a rarity.

true,true

[John M. Walker]

Multi strand aluminum wiring is still to code if used for a dedicated 240 VAC appliance circuit.

[John M. Walker]

Copper is the preferred feeder wire for manufactured homes.

[wvaidic]

Thanks for all of the answers.

Originally Posted by jwalker1

Copper is the preferred feeder wire for manufactured homes.

So, if you found aluminum as feeder wire for a manufactured homes you would write it up as a defect?

[Scott Gilligan, CMI]

Make sure aluminum SEC's have anti-oxidant paste installed at the lugs. Some manufacturer's use aluminum lugs, but the set screws are made out of steel. The paste helps prevent galvanic reaction between two dissimilar metals.

Stranded AL SEC's are perfectly fine and expect to find them everywhere.

[Jim Port]

While a good practice, the use of anti-oxidant paste is not required by the NEC, unless called for by the wire manufacturer.

[Robert Meier]

Originally Posted by Jim Port

While a good practice, the use of anti-oxidant paste is not required by the NEC, unless called for by the wire manufacturer.

I agree, you shouldn't be writing this up unless you know for sure that the specific lug manufacturer requires an anti-ox compound. To the best my knowledge most actually do not require it.

[mwolff]

Aluminum is fine if sized properly. What could be a problem is the type of insulation on the wire. Where conductors enter the residence they should have a temperature rating of 90C. In other words the insulation marking should have an HH rating... THHN XHHW. The higher rating is for a better fire rating. Many older homes will not have this type of insulation, but newer construction should. There again electrical can be case sensitive according to the AHJ.

[Robert Meier]

Originally Posted by mwolff

Aluminum is fine if sized properly. What could be a problem is the type of insulation on the wire. Where conductors enter the residence they should have a temperature rating of 90C. In other words the insulation marking should have an HH rating... THHN XHHW. The higher rating is for a better fire rating. Many older homes will not have this type of insulation, but newer construction should. There again electrical can be case sensitive according to the AHJ.

Mark what do you mean about a better fire rating and insulation type?

[Dan Bowers, CMI]

Wendy -

Aluminum stranded wire is probably the most common service entry wire in use in many areas. NO it would not be written /Just identified.

[mwolff]

Originally Posted by Robert Meier

Mark what do you mean about a better fire rating and insulation type?

Not all insulation types are the same. Such as thermoplastics or rubber. The type of insulation or coating on the wire will give it a specific temp.(heat) rating. By having a higher temperature rating it would be less likely to melt down the insulation in high current situations, thus a better fire rating.
For instance, certain direct burial conductors(service lateral) could be used up to the meter. If enough was left over after making the connection to the meter, we would just use the same wire to go from the meter to the indoor panel. But now that the wire has entered the building it should have a higher insulation rating.
Not sure if this could ever be written up though as I am quite new to the home inspection world.

[Jim Port]

Direct burial cable used to feed a service are not for use inside the house.

[Robert Meier]

Originally Posted by mwolff

Not all insulation types are the same. Such as thermoplastics or rubber. The type of insulation or coating on the wire will give it a specific temp.(heat) rating. By having a higher temperature rating it would be less likely to melt down the insulation in high current situations, thus a better fire rating.

I'm not understanding this concept. If the conductor is properly sized for it's connected load why would the type of insulation make any difference?