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when bonding at the boiler do you just cross bond the pipes or do you need to run earth cable back to the earth block at consumer unit? cheers
Spoken like a true spark, they bond everything.im no spark but pretty sure its not up to 17th and been told if in doubt bond it
Hi what can you say about gas boiler bc?
Interesting about the bonding, my sparks said that if you bond something that isn't done correctly in the first place your making a risk not curing it, giving the electricity somewhere to go.
Another point he babbled on about was what if someone has repaired a leak with plastic pipe (not a flexi, system 3) and not bonded between the two pieces of copper!
Hi what can you say about gas boiler bc?
The pipes are metal. The valves are metal. Usually connected together by a peice of metal
Basically cable's are copper and conduct electricity, copper pipe or virtually any metal does the same. So if you get an electrical fault it can travel along any metal, until of course somebody touches it.
So you have to ensure the resistance to Earth of the metal is low, because if its higher than you, electricity being lazy would rather travel through you to Earth than down the earthing route your cross bonding has made for it.
The easiest way is get hold of an Earth Loop tester and see what the resistance to earth is. An ordinary test meter will not tell you they usually only measure continuity and do not use a high enough test current. The earth loop tester tells you how much earth fault the earthing system can take.
Incidentally you should really do an earth test on a boiler as part of an overall electrical test if you have been repairing it, you can usually use the ohms on a multi-meter for it.
As already suggested though, providing the circuits are protected by an RCD, there is no longer any requirement for supplementary bonding (under boilers, sinks, baths etc)
If it's not, then it would be quicker to bond the pipework than it would be to do the tests. deal have a metallic strip integral to the boiler which acts as supplementary bonding.
Also do test whether or not you would need to cross bond the boiler, you would need an insulation resistance tester.
Insulation tests do not tell you how good the earth is just that one wire is insulted from the other and how good that insulation is. An Earth loop test tells you how much current your earth path will take. It would be point less earthing with fine wire it would burn out if you got a 230 volt 13 amp fault discharging to earth and leave your pipework still live and able to deliver a big shock for anybody touching it.
The RCD is intended to sense the current is the same voltage in both the Neutral and Positive wire in the cable. If its equal it stays open, if its more in one wire than it is in the other it shuts down because in an AC system it means the current is running to earth somewhere. But its relying on a mechanical RCD to always be working and not seized up over many years. That is why they have test buttons on them that should be tested every month or so. But who does?
It is right though, you do not have to supplementary bond providing the pipework is connected somewhere along its length to the main Earthing point and protected by an RCD. But how would you know it was connected without testing the earth and how good was the connection?
Anyway as Tamz says its not our job, but its interesting.
I am sorry you seem to be having trouble understanding me scoobydoo in my explanation of electricity and how it and earth bonding is supposed to work. I am not saying I am right and sambotc is wrong, we are talking about two different tests.
Please go careful scoobydoo and look up Earth loop testing as well as electrical safety testing and why they are done for both your own safety and your customers.
Don't get me wrong I am not advocating plumbers conduct these tests except the basic boiler safety electrical test which they are advised to do after a boiler repair and for which an insulation tester may be very handy. The question was about earth bonding not insulation testing.
I was alluding to the quality of earth and the amount of earth fault charge it can take. Sambotc was referring to the quality of the insulation isolating the wires from each other. They are two different things.
Most MI's will tell you a basic electrical safety test is required on a boiler after any electrical repairs. 🙂 🙂
Reply to the thread, titled "boiler earth bonding" which is posted in Boiler Advice Forum on Plumbers Forums.
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