Heat resistant junction box

[ChrisR]

I have to make a joint where heat-resisting flex is ok (inside a gas Back Boiler) but I don't know what's available.
Someone let the flex get too near the hot parts and it failed, so after I cut it back it'll be too short to reuse, and it's cemented in further back so I can't replace it.
I'm vaguely aware there are metal boxes and ceramic terminal strips, would that be best? (Only need to join LNE)

 

[Dartlec]

There may well be other better alternatives, but I would say the ceramic terminal strips would be a good bet, though it would need to be accessible for future inspection.

Alternatively I imagine crimps would be heat resistant to some extent, you could probably check with the manufacturer to check tolerances etc, and that way it will never need to be accessible. You could cover it with high temperature PTFE heat shrink that will apparently accept up to 260C - clicky - though not sure how you get it to shrink in that case!

Gavin

 

[plugwash]

though not sure how you get it to shrink in that case!

With the side of a HOT soldering iron? My soldering iron can be turned up to over 400 degrees celcuius which should be hot enough.

 

[ChrisR]

Thanks. The "ordinary" heat res flex, which I think is rated for 80º, is ok if you keep it away from the flames. This bit got to within about 80mm. It had gone hard and broken down.
The heat-shrink I've used would do I think, it doesn't "melt" at soldering iron temps and seals better than an open JB. I've got some non-plumbers solder (the pipe flux goes for the copper strands somewhat!)
Us plumbers use a blowlamp to heat it of course, its surprising how gently you can heat something with practice!

I didn't know about the ptfe heatshrink, it could be useful on electrode leads so I'll look out for it. The link you gave was US so I guess it isn't in every merchant