I have just been involved in a situation where temporary loss of neutral on a TNCS system caused thousands of pounds worth of damage. It seems this loss of neutral situation, either within or outside the installation, is occurring more frequently. SPDs are now commonly fitted but at DBS and generally with a Up in the order of 860v, so giving no protection on loss of neutral in a three-phase and neutral system. Cost benefit analysis across the national spectrum might not support a compulsion but is it time designers should be raising the issue with clients and at least offering a solution. On the other hand, is there a packaged solution?
You could just alter the pipe work in your installation, and ensure that it is all plastic, so that main equipotential bonding is not required. The gas main up to the house would be plastic in most cases, and just internal gas pipes would be meta
Other premises will have different issues - for example, premises that require LPS there's just no way of getting away from conductive stuff connected to the ground.
Oh, I think there is. I work in many 1970s houses, and even they have a main black plastic water pipe entering the house.
If needed we can install non electrically conducting inserts in metal water pipes where they enter the building if the pipe is metal.
There will be houses with metal gas, oil and water pipes entering the building of course.
In this part of the woods we have many householders that rely upon oil fired boilers. The oil pipe from the garden tank, which is sometimes plastic or metal, is raised off the ground on blocks. The metal pipe can be plastic covered. Electrical testing would be required to determine if the plastic covered oil pipe from garden tank to house boiler is an extraneous conductive part.
I come across old mains gas installations with a final lead pipe connection at the meter position. I would not like that semi-flexible lead pipe section to carry large fault currents and get hot then melt.
Many mains gas pipes that supply houses are yellow coloured plastic underground but convert to metal pipes internally. Electrical testing would be required to determine if the internal metal pipes are extraneous conductive parts and could carry diverted neutral currents, otherwise they may just be exposed conductive parts.
You could just alter the pipe work in your installation, and ensure that it is all plastic, so that main equipotential bonding is not required. The gas main up to the house would be plastic in most cases, and just internal gas pipes would be meta
Other premises will have different issues - for example, premises that require LPS there's just no way of getting away from conductive stuff connected to the ground.
Oh, I think there is. I work in many 1970s houses, and even they have a main black plastic water pipe entering the house.
If needed we can install non electrically conducting inserts in metal water pipes where they enter the building if the pipe is metal.
There will be houses with metal gas, oil and water pipes entering the building of course.
In this part of the woods we have many householders that rely upon oil fired boilers. The oil pipe from the garden tank, which is sometimes plastic or metal, is raised off the ground on blocks. The metal pipe can be plastic covered. Electrical testing would be required to determine if the plastic covered oil pipe from garden tank to house boiler is an extraneous conductive part.
I come across old mains gas installations with a final lead pipe connection at the meter position. I would not like that semi-flexible lead pipe section to carry large fault currents and get hot then melt.
Many mains gas pipes that supply houses are yellow coloured plastic underground but convert to metal pipes internally. Electrical testing would be required to determine if the internal metal pipes are extraneous conductive parts and could carry diverted neutral currents, otherwise they may just be exposed conductive parts.
