The IET is carrying out some important updates between 17-30 April and all of our websites will be view only. For more information, read this Announcement

Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Suggested Answer
  • Locked Locked
  • Replies 22 replies
  • Helpful Answers 1 Helpful answer
  • Subscribers 42 subscribers
  • Views 5012 views
  • Users 0 members are here
Options
You may also be interested in
This discussion is locked.
You cannot post a reply to this discussion. If you have a question start a new discussion

Is this method of earthing a water pipe permissible?

Arran Cameron

A house has the main earth terminal block located next to the electricity supply cable in a cupboard in the living room. The water supply is a blue MDPE pipe located in the kitchen that transitions to a copper pipe about 2m before the stop tap.

About 1m away from the earth terminal block are a pair of copper central heating flow and return pipes. These same two pipes are located right next to the copper water supply pipe in the kitchen.

The easiest, and most economical on cable, method to earth the pipes is to connect the earth terminal block to the central heating pipes in the living room, then connect the central heating pipes to the water supply pipe in the kitchen.

Is this permissible, or must a long length of earth cable be installed under the floorboards connecting the earth terminal block to the water supply pipe?

  • 0

    take a look at 542.2.6

  • 0

    If I have this correctly, your mains water copper pipe is near the MET, along with the copper flow/return CH pipes yes? So why can you not just run from the MET to the MWS pipe, then run a unbroken loop from that to the CH pipes?

    The CH pipes will most likely be already bonded via the cpc in the supply cable to the boiler/heater but it does no harm to bond them all together where the MWS (main water supply) pipe comes in.

  • 0

    What comes out of the ground Arran? Blue pipe or copper?

  • 0 in reply to Grumpy

    Blue pipe.

  • 0 in reply to whjohnson

    The MET is quite far away from the MWS. That's why I enquired about using the central heating pipes to connect the two together.

  • 0 in reply to Arran Cameron

    A blue plastic water pipe cannot introduce an external potential. On the face of it no bond is required.

    Gary

  • 0 in reply to Arran Cameron

    I'll light the firework, its still November ;-0

    no need to bond at all probably - a plastic pipe  not an extraneous conductive part capable of introducing an earth potential.

    You may be able to use the CH pipes as part of the connection, but I suspect someone will fail it on a later inspection - as I suspect they will if you follow my advice above as well.

    The no complaints no questions answer would be to run a cable from the metal pipe within the forst 60cm or so, to the MET in the other room, but electrically it may not be needed.

  • 0 in reply to mapj1

    Completely agree Mike. I usually "bond" any bit of copper connected to the blue incomer, even if it soon departs in Speedfit, as I simply can't be bothered to argue the toss!

  • 0 in reply to Grumpy

    Then you will be introducing a hazard that was not there before.

    Other people's ignorance is not a reason for doing something that should not be done.

  • 0

    I wouldn't be happy with using the CH pipes for main bonding because they may be removed or replaced. However, from the sound of it, the water supply does not need to be bonded.

    We haven't been told whether or not the CH pipes are in contact with the ground. If they cannot introduce a potential, no bonding is required at all.

Join us to get the best from IET EngX.

Joining EngX lets you personalise your experience so you stay up to date on the topics that interest you, plus you’ll be able to make connections who are looking to collaborate, exchange ideas and more.

Join us Not now

Community Rules & Guidelines