Kitchen aluminum 8-3 Rx good 40 amps?

[Jerseydaze]

Kitchen Renovation I need a 40 amp circuit for a duel fuel range .The existing circuit is on a 40 amp breaker and is 8-3 Rx aluminum I believe this is rated at 30 amps was there a time that This would have been rated at 40 amps ? If so can I reuse it?

 

[LEO2854]

Kitchen Renovation I need a 40 amp circuit for a duel fuel range .The existing circuit is on a 40 amp breaker and is 8-3 Rx aluminum I believe this is rated at 30 amps was there a time that This would have been rated at 40 amps ? If so can I reuse it?

I think you need a ground and a neutral , so no don't reuse it.

look at Table 310.15(B)(16). 60 DEG column you're only good for 35 amps.

334.80 Ampacity. The ampacity of Types NM, NMC, and NMS cable shall be determined in accordance with 310.15. The allowable ampacity shall not exceed that of a 60?C (140?F) rated conductor. The 90?C (194?F) rating shall be permitted to be used for ampacity adjustment and correction calculations, provided the final derated ampacity does not exceed that of a 60?C (140?F) rated conductor. The ampacity of Types NM, NMC, and NMS cable installed in cable tray shall be determined in accordance with 392.80(A).Where more than two NM cables containing two or more current-carrying conductors are installed, without maintaining spacing between the cables, through the same opening in wood framing that is to be sealed with thermal insulation, caulk, or sealing foam, the allowable ampacity of each conductor shall be adjusted in accordance with Table 310.15(B)(3)(a) and the provisions of 310.15(A)(2), Exception, shall not apply.
Where more than two NM cables containing two or more current-carrying conductors are installed in contact with thermal insulation without maintaining spacing between cables, the allowable ampacity of each conductor shall be adjusted in accordance with Table 310.15(B)(3)(a).

 

[kwired]

I think you could re-use a three wire cable if you are not extending the circuit and ground the appliance via the neutral.

I do agree your existing cable is only good for 35 amps.

 

[Ponchik]

OP mentioned 8-3 Rx. I assume Rx means romex? and if it is 8-3 it already has separate neutral and EGC.


I do agree with the 60C column requirement to be at 35A.

 

[kwired]

.. and if it is 8-3 it already has separate neutral and EGC.

If it were new cable -- very likely.

OP said it was existing. Back when it was common to use the neutral for equipment grounding on ranges and dryers, three wire cable with no equipment ground was pretty common. You could probably still special order some today, but there is no real demand for it so nobody stocks it anymore.

 

[Ponchik]

If it were new cable -- very likely.

OP said it was existing. Back when it was common to use the neutral for equipment grounding on ranges and dryers, three wire cable with no equipment ground was pretty common. You could probably still special order some today, but there is no real demand for it so nobody stocks it anymore.

I know which cable you are referring to. So, the older style cable was referred to as a 8-3? unlike today's cable that has 4 conductors but still referred to as 8-3, 12-3...

 

[Little Bill]

I think you need a ground and a neutral , so no don't reuse it.

look at Table 310.15(B)(16). 60 DEG column you're only good for 35 amps.

I think you could re-use a three wire cable if you are not extending the circuit and ground the appliance via the neutral.

I do agree your existing cable is only good for 35 amps.

OP mentioned 8-3 Rx. I assume Rx means romex? and if it is 8-3 it already has separate neutral and EGC.


I do agree with the 60C column requirement to be at 35A.

You guys must all have a different Table than what I have.
#8 Al in the 60? column is 30A not 35A.

 

[John120/240]

I know which cable you are referring to. So, the older style cable was referred to as a 8-3? unlike today's cable that has 4 conductors but still referred to as 8-3, 12-3...

Here it is understood that ground wire is included when you ask for 8-3 or 12-3. In years past we would ask for 8-2 which was two conductors (black & white) plus a ground.

 

[Ponchik]

You guys must all have a different Table than what I have.
#8 Al in the 60? column is 30A not 35A.

for 2011 it was changed to 35Amps for the aluminum.

 

[Little Bill]

for 2011 it was changed to 35Amps for the aluminum.

Never bought the 2011 since we never "graduated" to that one yet. Probably will jump to the 2014.

 

[kwired]

I know which cable you are referring to. So, the older style cable was referred to as a 8-3? unlike today's cable that has 4 conductors but still referred to as 8-3, 12-3...

What you ask for, what they give you, and what is marked on the cable may not all be the same thing.

Like I said "plain 3 wire cable" is pretty much a thing of the past as there is not many applications for it like there used to be.

If you have a cable marked 8-3, it likely has three insulated conductors in it. If you want it to have an equipment grounding conductor you need one marked 8-3 with ground.