Responsible or not

[Andy™]

A departure from BS7671 is something that does not comply with BS7671, but that will offer the same level of safety that compliance would offer.Protecting cables that are outside of safe zones with an RCD would IMHO offer the same level of protection as if those cables had an earthed metalic sheath. In fact as the RCD will operate quicker than the MCB, it might be seen that it offers greater safety.

but i dont agree with it in this case - like i said before, by sticking to 7671 you can remove all chances of nail becoming live, by it either not being anle to penetrate conduit, or the cbale not being there. by adding an RCD, there is still a chance that the nail can become live without the RCD tripping, and someone can then get a shock from it (by which time the RCD should have tripped).

so working to 7671: no chance of nail in this example becoming live

departure with RCD: chance nail could become live

so therefore it does not offer same level of safety as doing the job to 7671

another part is RCDs are known to fail. so whilst it may operate quicker than an MCB, it would be better to have done the work to 7671 meaning the MCB is guaranteed to trip, thats if RCD didnt trip first (if there was already one installed)

but i do agree that in some cases, a departure can be just as safe (possibly safer) as working fully to 7671

 

[spinlondon]

[quote name='Andy

 

[Lurch]

If this was the manner of compliance,

I'd be surprised if there's many installations of the type that this discussion started out about that would comply with 522.6.6 (i) (i.e. a normal house, normal kitchen, double socket on the wall) so a moot point, and I think you keep moving the goalposts.

This is like arguing with a woman!

 

[Andy™]

That is not so."522.6.6 (i) incorporate an earthed metalic covering which complies with the requirements of these Regulations for a protective conductor of the circuit concerned, the cable complying with BS 5467, BS 6346, BS 6724, BS 7846, BS EN60702-1 or BS 8436, or."

If this was the manner of compliance, the fault current would flow until the overcurrent device operated.

Whereas with my suggestion, the RCD would operate. It would operate at a lower current than the overcurrent device, and probablly quicker.

if there was a metallic covering, then the MCB will definately trip if its shorted L-E (assuming TN - TT would obviously have an RCD for this), and if RCD present, this would most likely trip before MCB

but in this case, the cable in question is not mechanically protected, or behind anything earthed, and is not in a safe zone. so there is a chance that a nail can be hammered into the live conductor and become live. your RCD will not trip until there is an imbalance, which could be through a person.

why did you jump to using a different cable to try and back up your point?

 

[Bez]

[quote name='Andy

 

[spinlondon]

[quote name='Andy

 

[niceguy]

Jesus, talk about a walk in the park.

Yes an RCD on a cable outside of a safe zone will offer the same protection as one IN a safe zone.

But the point you seem to be missing is that cables are NOT PERMITTED to be installed out of zones unless certain regs are met.

If you are removing an accessory and joining the cables, you either have to put the cables that are left in place it in steel conduit OR take it out.

With regards to circuits with no cpc's, these cables are already in safe zones.

How is this difficult to understand????

My bag is empty now.

 

[Apache]

I am of the opinion that protecting cables that are not in safe zones with an RCD will offer the same level of protection as cables that are in safe zones or in walls with structural metal parts that are protected by RCD.

It clearly won't. People hang pictures, attach can openers, kitchen roll holders, soap trays in kitchens roughly at socket hight. The cable IF OUTSIDE OF A SAFE ZONE could easily be damaged.

I am not in the trade, nor are my parents, but myself and my family are fully aware of the concept of safe zones when hanging pictures, putting up shelves etc.

To my mind this is very similar to the advice given by the ESC regarding lighting circuits that have no CPC.

Not really as to comply AFAIK all fittings have to be class II and therefore there is no chance of a person coming into contact with any current due to faults. Unlike with your 'ignore safe zone, fit RCD and then hang a picture' idea.

 

[Andy™]

I have not jumped to using a different cable. That is the cable detailed by Regulation 522.6.6(i).It does not matter if there are many installations using this type of cable.

The criteria for departures from BS7671, is that departures must offer the same degree of safety, that compliance with BS7671 would offer.

The Regulations that require RCD protection to cabels refer only to cables in safe zones that do not have any other means of additional protection, and cables that are in walls or partitions that have metal structural parts.

I am of the opinion that protecting cables that are not in safe zones with an RCD will offer the same level of protection as cables that are in safe zones or in walls with structural metal parts that are protected by RCD.

To my mind this is very similar to the advice given by the ESC regarding lighting circuits that have no CPC.

you have jumped to a different wiring method - were talking about a T&E not in a safe zone - therefore adding an RCD does not give the same protection as it would by sticking to 7671 and removing said cable, or making it comply with 522.6.6 (i)-(iv), i.e earthed steel conduit.

 

[Bez]

All those years you chaps have been putting cables in safe zones, when all along you could have gone diagonally accross walls, stuck em under the carpet, wound em' round the curtain rails, and all it needed was an RCD, well ****** me.

 

[Andy™]

i know.. the amount of time & effort i could have saved!

 

[kme]

I think my one & only post on this topic is going to have to be:

I thought that if I could show that there are acceptable ways to comply with BS7671 without complying with BS7671, then it would be easier to explain that my solution is a way of complying with BS7671 without complying with BS7671.

Forgive me if my command of the english language has gone defective here - I simply cannot manage to get my head to process these two comments.

It is akin to eating an orange without eating an orange, isn`t it?

As to the actual "discussion", Who says that "putting an RCD on the circuit" is equivalent, or better, than following 7671? Just you? Or have you been given this idea from somewhere else, i.e. scam provider or IET etc...

Just curious...

KME

 

[Lurch]

Whilst the latter portion of this thread does appear somewhat pointlessly and longwindedly drawn out I do like threads that make you refer to regs and wotnot and have a good read of the odd couple of well used sections. Having said that, back to RRCi now.

 

[batty]

Well that has taken me now nearly an hour to catch up on this thread. I may be wrong but I thought all cables have to be in zones even if they are ones that don't need an RCD and I also thought you cannot use an RCD to protect cables that are outside zones. Even if this is wrong I think only a poor electrician will install cables outside zones.

Batty

 

[Bez]

Oh Noooooo, Another can of worms

 

[Apache]

I think my one & only post on this topic is going to have to be:

You have posted 3 times in this thread

 

[Lurch]

I may be wrong but I thought all cables have to be in zones even if they are ones that don't need an RCD

read 522.6.6 and 522.6.7.

and I also thought you cannot use an RCD to protect cables that are outside zones.

That is the whole point of this thread I think.

 

[Andy™]

Well that has taken me now nearly an hour to catch up on this thread. I may be wrong but I thought all cables have to be in zones even if they are ones that don't need an RCD and I also thought you cannot use an RCD to protect cables that are outside zones. Even if this is wrong I think only a poor electrician will install cables outside zones.Batty

522.6.6 - if mechanically protected etc, they can go anywhere.

if not mechanically protected, they must go in a safe zone as per 522.6.6 (v), and may need RCD'd as 522.6.7

main point to the long discussion was spin saying that they it doesnt have to go in a safe zone as long as its RCD'd (even though his argument constantly changes?)

 

[batty]

[quote name='Andy

 

[Andy™]

So you would put swa up middle of wall under plaster?

yes. but i would try and avoid it, and keep to safe zones where possible to try and avoid any potential damage