Manoj asks this question, which is about the use (or otherwise) of multiple earth spikes to earth a central heating system TT electrical installation. It has been answered by the NICEIC (Theme – Fire, Safety and Security):
This Q & A is one of thousands posted in our Technical Expertise area, and answered on a daily basis by our Voltimum Experts.
Question: I’ve recently looked at a central heating job and need to get a main bonding conductor to the outside oil line, but I have no clear way of getting back to the origin of the installation with my earth (TT installation).
Can I install another earth spike local to the heating boiler and take my main bond off this?
I can see no reason why I should not do this, but want to be sure.
Answer: The main protective bonding of the installation needs to be taken back to the main earth terminal, and the use of an additional spike is not acceptable.
Your spike could have a resistance higher than the TT spike and, therefore, would introduce a difference between the pipework and the earthing arrangement within the installation.
The other issue is, does the oil pipe actually run underground? If it is taken from the outside, but is not in contact with the general mass of earth outside, then the regulation does not require for it to be bonded.
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