Can you help with RCD/regs/Earth leakage questions

[bs7671]

1.What would leak to earth naturally,I mean in terms of earthing arrangements(combined protective and functional) 2.Where in the regs book can I find about RCDs in relation to where and when installation is required.Any help or guidance would be great.Thanks peps

 

[Sparky Ninja]

1. Leak to earth naturally? Could that refer to leakage current? That occurs under normal operating conditions.

2. The RCD in is mainly introduced in section 415, and then when it is necessary to be used further on in places like special locations etc, it will refer back to that section in the book. I cannot think of a place where it will give you every example in one location.

 

[telectrix]

common practice now is to RCD or RCBO everything except fire alarms, freezers or anything that would cause major probs if supply lost. However, if no RCD on these, cables must not be buried in walls unless enclosed in earthed conduit, ok if surface. that's my interpretation. no doubt someone more knowledgeable will correct me if i wrong

 

[bs7671]

Thanks guys I got the RCD one nailed but it's the other question that's messing me up.Ok the actual question is 'Describe the earthing arrangements for combined protective and functional purpose's with particular reference to things that leak to earth naturally?I have found out that laptops do this and have a switched mode protector but am I barking up the wrong tree?Where is this type of thing in BS7671 ?Any advise on aswering this question would be great.Thanks guys

 

[Sparky Ninja]

Thanks guys I got the RCD one nailed but it's the other question that's messing me up.Ok the actual question is 'Describe the earthing arrangements for combined protective and functional purpose's with particular reference to things that leak to earth naturally?I have found out that laptops do this and have a switched mode protector but am I barking up the wrong tree?Where is this type of thing in BS7671 ?Any advise on aswering this question would be great.Thanks guys

543.5.1

 

[telectrix]

microwaves leak naturally. so do dogs when there is a tree close by

 

[bs7671]

Lol sometimes without a tree in sight doh!

 

[telectrix]

bitches are the worst. we got so many brown patches on the grass, they look like cowpats. bloody rottweilers

 

[JUD]

common practice now is to RCD or RCBO everything except fire alarms, freezers or anything that would cause major probs if supply lost. However, if no RCD on these, cables must not be buried in walls unless enclosed in earthed conduit...

...or under the supervision of a skilled or instructed person.

Cables can still be buried in walls without RCD protection as long as they're buried >50mm from the surface.

 

[Baal]

Any item of equipment with a switched-mode power supply will have designed earth leakage, recommended design figures are in the order of 1mA.

BS7671:2008 has requirements for such circumstances in 543.7