'Small' flexible aluminum connections

[tshephard]

Hi all -thanks for any input...

Changing a 240V cooktop, calls for 40 amp circuit, manual instructs special procedures if supply is also aluminum (such as copper pigtail between ALs). I have #6 AL SE XHHW to jb for old stove - no problem with ampacity.

The cooktop comes with 6 feet of #10 aluminum XLPE (seems OK for OEM), with about 50 strands (in FMC). As I read, I seem to crossed a flexible conductor limit. But my supply guys act like I'm the only one ever to ask for flex, dual rated connectors.

Am I researching this right, or have I overlooked something obvious? Am I making this too complicated? Would split bolts (Al/Al type) inherently be flex rated? Is that flex rating only for screw and crimp types connectors or for all? What's really different physically in a flex connector?

I wonder because the listed device does call for special connections because of Al/Al hazard, but never mentions the high flexibility of the conductor as a special consideration.

Another thing that bothers me is that the FMC on the cooktop came with nice, neat rubberized cloth tape around the conductors (as though for neatness), and then explictily covering the end of the FMC where it would go into a flex connector for about 2 inches - as though to prevent any grounding to the connector at the box.

I have cut through the tape for flex connector continuity, and used the old purple CU/AL wirenuts as I look for the right or best connectors.

Any help?

 

[curt swartz]

The factory conductors supplying the cooktop are not aluminum. They are tinned copper.

 

[Jim W in Tampa]

nec will require the outlet (junction box) to be 4 wire enen if cook top does not use a neutral.

 

[tshephard]

I went back and googled all the numbers on the conductors and Curt is right if it's labled correctly AWM 3321- I would have sworn....
But I'm still left with the fine strand situation - it says 105 #30s. Even as copper, do the new rules and ratings require special 'flex' connectors for stationary, residential equipment with fine standed conductors?

 

[tshephard]

Anyone?

I'd still appreciate some advice on the flex issue, and what seems like the manufacturer deliberately isolating the FMC.

Thanks all.

 

[LarryFine]

In no particular order:

The conductors are indeed tinned copper, not aluminum, which would break, and purple wirenuts should be adequate.

The tape is to protect the wires from the flex before connector installation. I suggest removing it and adding a bushing.

The flex is well grounded through its connection at the appliance end, so even if you leave the tape, it's still grounded.

Just to add, with a 3-wire supply, such as your SE, the white and bare/green should be joined at the J-box joints.

 

[curt swartz]

Definitely do NOT use purple wire nuts. The are not rated for #6 conductors. I would use NSI/Polaris connectors (IT-4) or split bolts.

 

[tshephard]

Larry/Curt - thanks (Larry - I'm Richmond too, you've helped me before!)
I ended up ordering Ilsco connectors that are both dual and flex rated - $80 for 6 (wall oven and range).
The Ilsco tech guy told me they put a special 'spring washer' on the 'bolt' instead of a flat or a point.

I gonna' go with it, I think I did all the research I should, but I'm still surprised they could consider it adquate warning without mentioning...

A The conductors have more than 'B' strands, and thus seem to need listed flex connectors (apparently no wirenuts qualify, and I could find no splitbolts that said flex rated)
B That tape that effectively isolates the jb/metal raceway connection. The way they did it was like it was supposed to isolate, and neat and pretty as though to last - not just slipped up inside to protect insulation. I think the average appliance swapper would have thought it was supposed to stay in place.

Thanks guys...