L
LlandrilloSpark
I went to a customer today who told me she had a pre electrical survey done by BG before they would agree to connect a new boiler, the "survey" was done by the sales guy.
Basically she told me that he said BG would not connect the boiler because he did a "socket and see test and he got more than 100 ohms???",he didnt remove any loads or isolate anything whilst doing this test, after getting this reading he promptly went outside looking for an earth rod.
If the guy had the common sense to actually look in the right meter box(he looked in the gas meter box), he would of noticed the supply is a TNCS which was installed in 2001, 35mm tails from the road, 25mm going through the outer walls and into the basement.
I carried out a Zs test on each floor of the house, the results were 2.16ohm, 2.01ohm,1.95ohm and 1.98 ohm all on 32A mcb's, all 3 circuits exceed the OSG max permitted figures,
I then took 5 Ze readings, they varied from 1.05ohm - 1.15ohm so its fair to say its the high Ze which is the problem.
The installation is protected by a 30ma RCD Main Switch, so perhaps this problem was spotted earlier.
I tested the RCD fully and the times come back 17.8ms(x1) and 7.8(x5)
My query is should or can British Gas refuse to connect the boiler to a circuit which is protected by a fully working RCD, when the Zs is averaging 2ohms when the advice the IEE gives to us is that we can safely use circuits on RCD's when the loop well exceeds 21ohms or more.
I have to write a report for the customer and also advice on contacting the DNO so i'd appreciate your valued feedback!!
Cheers
Basically she told me that he said BG would not connect the boiler because he did a "socket and see test and he got more than 100 ohms???",he didnt remove any loads or isolate anything whilst doing this test, after getting this reading he promptly went outside looking for an earth rod.
If the guy had the common sense to actually look in the right meter box(he looked in the gas meter box), he would of noticed the supply is a TNCS which was installed in 2001, 35mm tails from the road, 25mm going through the outer walls and into the basement.
I carried out a Zs test on each floor of the house, the results were 2.16ohm, 2.01ohm,1.95ohm and 1.98 ohm all on 32A mcb's, all 3 circuits exceed the OSG max permitted figures,
I then took 5 Ze readings, they varied from 1.05ohm - 1.15ohm so its fair to say its the high Ze which is the problem.
The installation is protected by a 30ma RCD Main Switch, so perhaps this problem was spotted earlier.
I tested the RCD fully and the times come back 17.8ms(x1) and 7.8(x5)
My query is should or can British Gas refuse to connect the boiler to a circuit which is protected by a fully working RCD, when the Zs is averaging 2ohms when the advice the IEE gives to us is that we can safely use circuits on RCD's when the loop well exceeds 21ohms or more.
I have to write a report for the customer and also advice on contacting the DNO so i'd appreciate your valued feedback!!
Cheers
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