J-box in high ambient temperature environment?

[sw_ross]

I did a little work at a brewery last week hooking up power to a new heating element in their 900 gallon hot water tank.
It’s a 9kW element at 240v 3P so it’s only pulling about 22 amps.
There’s 2 elements, both are 9kW in this tank.
The problem is that the heat given off by the tank when it heated up makes the ambient air temperature around the j-box very high and the wire insulation melts back to a point where things short out in the j-box, shorting out the element and tripping the breaker.
Here’s a picture of the old element’s j-box:

I’m not sure the best solution to the problem. I decided to upsize the wire to #8 and I used some heat shrink and added a layer of tape over the crimp connectors where the wire is crimped to try and mitigate the insulation melting issue.

I’m not confident that upsizing the wire is the best solution. The #10 wire is more than adequate for the current.

Any suggestions for an alternative solution would be much appreciated.

 

[infinity]

We've hooked up jacket heaters on generators that required a minimum conductor temperature of 125° C. We used type Z insulated conductors rated at 150° C in dry locations.

 

[sw_ross]

I asked my supply house about a higher temp wire. The salesman that I spoke to didn’t know what to suggest.

 

[Sberry]

I used some heat shrink and added a layer of tape over the crimp connectors where the wire is crimped to try and mitigate the insulation melting issue.

Some strip back may have helped, all that is just retaining heat. I also would be thinking about some appliance wire here.

 

[MTW]

SRML is high temp wire used in commercial cooking equipment for internal wiring in grills and fryers. Also used for motor leads. If you get some temp rated crimp terminals to go with it, you will be good to go for the long haul.

SRML Motor Lead Wire | Allied Wire and Cable

SRML wire is a high-temperature wire that can be used in settings that are hazardous or for motor lead wire. Excellent flexibility and fire resistance.

www.awcwire.com

 

[masterinbama]

12 AWG MG UL 5335/5107 450°C High-Temperature Wire

Specification: MG UL 5335/5107 450°C High Temperature Wire performs well in extreme conditions due to its temperature rate of 450°C. Unlike other high temperature wires, MG UL 5335/5107 450°C does not require additional protection from temperatures, saving costs significantly. MG electrical wire...

nassaunationalcable.com

I have used this in the past on annealing furnaces in an aluminum plant