Ask Electronics

So I'm not sure what the right community for this is but I'm hoping yall can help. I'm a refrigeration service tech and recently I was tasked with replacing a sensor in a room used to store ethanol drums. Due to the nature of the room every device in it had to be rated explosion proof and I couldn't use any tools that could pose any risk of ignition (no heat gun, basically nothing with an electric motor, and definitely no open flames) while working in there. Normally when I splice wires I use heatshrink to cover the splice simply because it looks far more professional than electrical tape and it holds up better over time. However in this case I could not figure out any way of shrinking said heatshrink without posing a potential ignition hazard so I was stuck just wrapping the splice in tape. We do a lot of work for this company so I'm hoping to find a better solution for the next time I am in a similar situation.

So do any of you know any way to shrink heatshrink without posing an ignition hazard or am I stuck just using tape in those situations?