plastic pipe fittings

redface · Jun 24, 2011

now im doing a pir on a large old building now because there are so many additions there are loads of plastic speed fit joints on copper pipe work now i am putting this down as not acceptable because there is no continuity on the pipe work. am i right in saying this as it has never been picked up in the last report the installatin was acceptable i dont want them thinling im making it up for more work im just doing my job. what would u do ? thanks

timo1 · Jun 24, 2011

Hi, I thought that the provision of an RCD was used in order to overcome this? I think you can get around it if you RCD protect the installation, although I dont have my BRB to hand to assist with a reg.

nickblake · Jun 24, 2011

The main bond to services water etc is at the incomming supply ,this stop any potential faults comming into the building from the outside , if the pipes have been insulated from the main earth by these joints then there is no problem supplimentary bonding can be omited when RCD protection is provided to all circuits and providing certain criteria has been met

redface · Jun 25, 2011

ok but what if there is a fault to a ac unit or boiler or a bit of equiptment which is plumbed in or a ice machine or a cable melts over the copper pipe it will just be live and not blow a fuse or anything also how would a rcd work if there is no continuity in the pipe and it can happen.
and it is a large building with about 200 circuits so a rcd is not going to happen

malcolmsanford · Jun 25, 2011

If there is a fault on a piece of equipment I would hope that it never relied on bonding to disconnect the fault to be honest. Earth limits the fault duration, and bonding limits the touch voltage. So for a class I piece of equipment I would hope that your CPC would carry away the fault and if the circuit is designed correctly then it will trip the device.

You can check these pipes to actually see if they are extraneous conductive parts. Also you only need to fit suplementary bonding in a special location ie a room containing a bath or shower.

ezzzekiel · Jun 25, 2011

main earthing will limit the duration of a fault and main bonding limit the magnitude.

any leakage to earth would cause a imbalance in the rcd causing it to operate, bonding the services will allows metalwork to rise to same potential under fault conditions.

Malc types quicker than me

where a mixture of plastic and copper pipework is used in a building main bonding should still be carried out at incoming services position, where the intake and complete installation is all plastic then main bonding may be ommited.