Main earth bonding
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kloedjob3
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Joined: Sat Apr 04, 2009 12:41 pm

Main earth bonding

by kloedjob3 » Sat Apr 04, 2009 12:51 pm

As part of a warm front central heating assessment an electrician has carried out an inspection and told us that our bungalow is not earthed.
:evil: He says we need an earth and RCD fitting between the fuse box and sealed unit, an earthing spike and may also need bonding for the main gas and electric pipes. He says he got a reading of 1600 ohms instead of around the desired 0.4 ohms. He also says it must be done this way as we have an overhead supply which is not suitable for any other kind of earthing. It's all a bit double dutch to me but hopefully someone can explain a bit more. He was a little reluctant to explain anything as he is not going to be doing the work. :(
The reason we are going for the warmfront grant is that we cant afford all of the money for the new central heating. With all this additional work on the electrics the budget is looking like going out of the window.
Does this sound familiar to anybody out their and how much is all this likely to cost? :?:

kbrownie
Project Manager
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Joined: Mon Mar 05, 2007 9:36 pm

by kbrownie » Sat Apr 04, 2009 7:20 pm

Hi kloedjob3,
Your property is likely to be in a remote area where installing underground cable is not practicable, so this means that an earthing arrangement will best made via a earth electrode or spike. This is known as a TT system and the installation should be protected by and RCD.
All system now need RCD protection to Comply to BS7671:2008. But TT systems always have needed it.
Your Supply Authority don't have any legal requirement to offer this earth to you, so you will need to have it done.
Cost depends where you live
The assessent sound correct and it does need addressing ASP. Ohms reading way too high should be much lower, The top limit is 200 ohms on this type of arrangement and that's not very good.
Regards
KB

BLAKEY1963
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Re: Main earth bonding

by BLAKEY1963 » Sat Apr 04, 2009 7:27 pm

[quote="kloedjob3"]As part of a warm front central heating assessment an electrician has carried out an inspection and told us that our bungalow is not earthed.
:evil: He says we need an earth and RCD fitting between the fuse box and sealed unit, an earthing spike and may also need bonding for the main gas and electric pipes. He says he got a reading of 1600 ohms instead of around the desired 0.4 ohms. He also says it must be done this way as we have an overhead supply which is not suitable for any other kind of earthing. It's all a bit double dutch to me but hopefully someone can explain a bit more. He was a little reluctant to explain anything as he is not going to be doing the work. :(
The reason we are going for the warmfront grant is that we cant afford all of the money for the new central heating. With all this additional work on the electrics the budget is looking like going out of the window.
Does this sound familiar to anybody out their and how much is all this likely to cost? :?:[/quote]

KLOEDJOB3

YES sounds like you have a overhead TT Supply.
A check with your electricity distribution supplier will confirm
this , if P.M.E COULD not be provided . A T.N.C.S ( P.M.E )
SUPPLY would
give you max of 0.35 omhs .( supplier fits a link to provide earth faciity)
if you are indeed stuck with your TT System , then yes you
need 30 milliamp R.C.D Protection on every circuit .
earth rod and inspection earth cover. 16 mm2 earth cable.
AND AS the electrician says gas and water bonds.
you need to get quotes in your area , from registered part p electricians . ( members of E.C.A , NAPPIT , N.I.C.E.I.C , ECT ) prices in my area would be about £ 250 - 300 including testing and certification .

BLAKEY1963

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