N
NickD
Wotcha,
I got asked to follow up on a low (<1Mohm) whole-installation (L+N)-E IR result picked up on an EICR (not done by me) on a domestic property. Testing only at 250Vdc, it turned out this is is the result only if the C.H. boiler is in circuit. With boiler isolated, same test yields >100Mohm.
This means (presumably) that whoever did the EICR hit the C.H. boiler with 500Vdc, (L+N)-E. And hadn't isolated it during test despite saying it would be on their extent/limitations. Boiler appears to still be working normally on brief functional testing.
So I can report that it's not a fixed wiring issue. But having taken the reading, I feel duty bound to say something about the boiler reporting <1Mohm. 0.94Mohm (L+N)-E @250Vdc, to be exact. (And mentioning it's presumably been tested at 500Vdc).
Boiler is Class I equipment. Code of Practice for In-Service I&T of Electrical Equipment p.75 says minimum (L+N)-E IR values for Class I equipment is 1Mohm, or 0.3Mohm for heating & cooking equipment with rating >= 3kW. Now I assume that the 3kW rating figure only relates to electrical heating power, not the total heat output of non-electrically-heated heating equipment, and so the 1Mohm figure is the one that applies here. Do I assume correctly?
I'm also aware of the notes saying that certain heating appliances may be unable to meet the requirements, also about transient suppressors where fitted etc. so I've half a mind to ask the manufacturer (Potterton) what they specify for the equipment.
What would you do?
Cheers.
I got asked to follow up on a low (<1Mohm) whole-installation (L+N)-E IR result picked up on an EICR (not done by me) on a domestic property. Testing only at 250Vdc, it turned out this is is the result only if the C.H. boiler is in circuit. With boiler isolated, same test yields >100Mohm.
This means (presumably) that whoever did the EICR hit the C.H. boiler with 500Vdc, (L+N)-E. And hadn't isolated it during test despite saying it would be on their extent/limitations. Boiler appears to still be working normally on brief functional testing.
So I can report that it's not a fixed wiring issue. But having taken the reading, I feel duty bound to say something about the boiler reporting <1Mohm. 0.94Mohm (L+N)-E @250Vdc, to be exact. (And mentioning it's presumably been tested at 500Vdc).
Boiler is Class I equipment. Code of Practice for In-Service I&T of Electrical Equipment p.75 says minimum (L+N)-E IR values for Class I equipment is 1Mohm, or 0.3Mohm for heating & cooking equipment with rating >= 3kW. Now I assume that the 3kW rating figure only relates to electrical heating power, not the total heat output of non-electrically-heated heating equipment, and so the 1Mohm figure is the one that applies here. Do I assume correctly?
I'm also aware of the notes saying that certain heating appliances may be unable to meet the requirements, also about transient suppressors where fitted etc. so I've half a mind to ask the manufacturer (Potterton) what they specify for the equipment.
What would you do?
Cheers.
