IEE 17th Edition - What is new?

[savilleorange]

Just for my curiosity could some one please explain the major changes in the rules introduced recently.

 

[GaryMo]

Look through previous posts or try Google.
In fact, I just typed in 'major changes 17th edition'. Easy isn't it?

http://www.voltimum.co.uk/news/8849...n/Summary-of-changes-in-the-17th-Edition.html

http://www.elecsa.org.uk/downloads/public/3382 factsheet.pdf

 

[savilleorange]

Thanks for that Gary.

 

[GaryMo]

No problem

 

[ebee]

This might be an idea:-

17th Edition overview

RCD for :-

1/ All sockets 20A or less to be protected
except where specifically intended and clearly labelled for one specific item (such as fridge/freezer)

2/ All cables buried 50mm or less
(unless in SWA or earthed conduit – extremely unusual in a domestic setting)

3/ Cables buried at any depth if any metallic construction is used (not screws and nails
but more substantial components)

4/ All items in a bathroom

Insulation resistance up from 0.25M to 0.50M for SELV and PELV and from 0.50M to 1.0M for 500V & 1000V tests

Supplementary bonding in bathrooms may be omitted only if ALL of the following apply
Everything in bathroom is RCD protected.
Main bonding is in place.
There is continuity between bathroom pipework and main bonded pipework

Floor and Ceiling heating systems are included in part 7 – special locations and installations

Dual RCDs or RCD and/or RCBOs to reduce unwanted tripping of circuits faults on unrelated circuits.

Bathrooms – zone 3 removed and sockets allowed if not less than 3M from bath

Construction/demolition sites & horticultural.agricultural sites disconnection times reduced to 0.2 seconds and 25V limit removed.

TT also reduced to 0.2 unless MCB disconnection of earth faults can be met (very
unusual)

Volt drop of 4% now becomes 3% for lighting & 5% for other

EFLI based on 230V(Uo) not 240V (Uoc) so altered slightly

E & OE

 

[savilleorange]

Brilliant post ebee. You know how to hit the nail on the head.

I was intrigued to see enormous price hike of the Wylex Consumer Unit at Screwfix until I noticed "dual RCD".

 

[dingbat]

It's all well and good for people to look for simple lists of changes, but did you know how to use the regulations before they changed?

It is incumbent on all who design, install, inspect, test and certify electrical work, at whatever level, to understand the requirements as they apply in individual cicumstances. If all the requirements could be summed up in half a page of notes, why do the regs extend to some 389 pages?

If you are carrying out electrical work for profit you have no excuse for not having a thorough working knowledge. If you are looking for DIY advice it is important that you realise the regulations are far more than a simple list of dos and don'ts.

 

[savilleorange]

Point taken dingbat, I admire your integrity.

 

[TANNERS]

are the designated routes still applicable ?

or can you run cables anywhere less than 50mm unprotected as long as theres a rcd?

 

[ericmark]

The link seems to be BS7671:2008 not BS7671:2008 amendment 1. I have not as yet got a copy of amendment 1 but the talk before it was released was it would have sections covering hospital work which was not included before.

There was also talk about relaxing the rules on RCD for additions to existing circuits. It would be interesting to hear if this has in fact been done?

 

[riveralt]

The link seems to be BS7671:2008 not BS7671:2008 amendment 1. ?

Possibly because its a very old post eric

 

[ericmark]

Sorry missed date on post.

 

[EFLImpudence]

are the designated routes still applicable ?

Oh, yes.

or can you run cables anywhere less than 50mm unprotected as long as theres a rcd?

No. Wrong way round.

You can only run them outside 'safe zone' if protected.
That is mechanically protected - earthed steel conduit or 3mm steel.

Unprotected cables are ONLY allowed in 'safe zones' and if <50mm. deep must be RCD protected.
Bear in mind in 'normal' properties cables cannot be buried that deep, anyway.

 

[mfarrow]

Unprotected cables are ONLY allowed in 'safe zones' and if <50mm. deep must be RCD protected.

Not quite, if you're >50mm deep and not in a wall made from/containing metallic parts then you don't need any protection for that cable, RCD or mechanical, and you don't need to worry about safe zones.

 

[EFLImpudence]

Unprotected cables are ONLY allowed in 'safe zones' and if <50mm. deep must be RCD protected.

Not quite, if you're >50mm deep and not in a wall made from/containing metallic parts then you don't need any protection for that cable, RCD or mechanical, and you don't need to worry about safe zones.

That may be so. Would that be classed as a 'safe zone'?
However, it is not possible in a 'normal' property (wall cavities no longer being an option).


Would you consider burying a cable >50mm in the mortar and routed (zig-zagging) around the stone (of a stone wall) to be good practice, as in this thread?
//www.diynot.com/forums/electrics/cable-extension.309832/#2275462

No one has suggested it.