Voltage on the gas pipeline: the boiler machine knocks out and the protective conductor melts

Konstantin asks:

Found out today smoke from a double-circuit heating boiler, while the machine worked. When the machine was turned on again, the smoke resumed. Having disconnected the boiler from the network, I partially disassembled it and found a melted yellow-green wire. Next, I disconnected a suitable gas pipeline from the boiler (corrugated metal pipe) and reconnected the boiler to the network.

There was no more smoke. When I tried to connect the gas pipeline to the boiler when it was connected to the electrical network, it began to spark, which made it necessary to change part of the gas pipeline to a rubber hose. The boiler is currently out of order, the board is changing. How can I avoid such situations in the future. Because the workers of the gas service "freeze" from this problem). Thanks in advance.

Since the yellow-green wire is ground, I assume that you have a grounding circuit, it can spark and melt only as a result of a short circuit, the more the machine is triggered. This, in turn, can happen for two reasons:

1. Either there is voltage on your "ground", and since the gas pipeline is most likely grounded, there is a short circuit or, if you like, a leak.
2. There is a potential on the gas pipeline, and in the boiler it somehow connects to the body. The result is the same.

You need:

1. Decide where you got the yellow-green wire from and what it is connected to.
2. If you have a ground loop in the yard or under the support, then check all the contacts of the protective conductor (the so-called "metal connection").
3. Check for voltage on the ground and on the gas pipeline.

According to. NS. 1.7.82 chapters 1.7. PUE "If the gas supply pipeline has an insulating insert at the entrance to the building, to the main equalization system potentials, only that part of the pipeline is connected that is relative to the insulating insert on the side building."

That is, there must be an insulating connection at the entrance to the building, after which the gas pipeline is connected to the equalization system. potentials (to ground) .The fact that you put a rubber hose and you did something similar to this is the most insulating compound. that is, they removed the galvanic connection between the gas pipeline and the gas system of your boiler.