why does reg. 543.2.3 prohibit the use of a gas pipe as a protective conductor? After all it can be main bonded and then carry substantial currents under certain conditions.
The risk is nil while the pipes remain closed. Nasty things happen, as they have to plumbers as well, when a fitting or union is loosened to change a meter or an ECV and current was flowing.
There is at least one case of a plumber being killed while removing a stopcock in a supply pipe outdoors, as he unwittingly also interrupted the neutral return for quite a lot of load at the same time. With gas far smaller currents could still pose an ignition hazard during disconnection if a spark can be drawn.
Insulating joints (IJs) are supposed to be the fix for that, but are rarely seen.
The risk is nil while the pipes remain closed. Nasty things happen, as they have to plumbers as well, when a fitting or union is loosened to change a meter or an ECV and current was flowing.
There is at least one case of a plumber being killed while removing a stopcock in a supply pipe outdoors, as he unwittingly also interrupted the neutral return for quite a lot of load at the same time. With gas far smaller currents could still pose an ignition hazard during disconnection if a spark can be drawn.
Insulating joints (IJs) are supposed to be the fix for that, but are rarely seen.
