IET logo
 
IET
Decrease font size
Increase font size
Topic Title: 18th EDITION DPC
Topic Summary: NOW LIVE
Created On: 02 June 2017 10:55 PM
Status: Read Only
Linear : Threading : Single : Branch
<< 9 10 11 12 Previous Last unread
Search Topic Search Topic
Topic Tools Topic Tools
View similar topics View similar topics
View topic in raw text format. Print this topic.
 27 July 2017 05:25 PM
User is offline View Users Profile Print this message



Fm

Posts: 1710
Joined: 24 August 2011

Surface conduit?
 27 July 2017 05:30 PM
User is offline View Users Profile Print this message



dustydazzler

Posts: 1332
Joined: 19 January 2016

Yeah nice bit of surface conduit or
Sticky back trunking if I'm feeling lazy..
Or if I'm feeling proper badger surface clipped to the skirting boards and round the door frames
Beautiful
 27 July 2017 05:35 PM
User is offline View Users Profile Print this message



sparkingchip

Posts: 9953
Joined: 18 January 2003

Metal saddles on the conduit and metal clips within the sticky back trunking will help to make it all compliant.

Andy B
 27 July 2017 05:37 PM
User is offline View Users Profile Print this message



dustydazzler

Posts: 1332
Joined: 19 January 2016

Thinking about it , I might subby the conduit work out to the old man he can do it in 20mm galv and then I can just pull the Earth cable in after.
Board changes are gonna get real expensive next year....
Better practice sucking my teeth a bit more
 27 July 2017 09:01 PM
User is offline View Users Profile Print this message



ectophile

Posts: 746
Joined: 17 September 2001

On the plus side, the lump of old pipe poking out of the floor of my meter cupboard isn't just a redundant bit of old gas pipe that nobody could be bothered to remove. Instead, it's an 18th edition earth electrode, already installed!

-------------------------
S P Barker BSc PhD IEng MIET
 28 July 2017 12:15 AM
User is offline View Users Profile Print this message



mapj1

Posts: 9346
Joined: 22 July 2004

except presumably, it was disconnected because it had rusted through somewhere - as has a great deal of black iron, hence the desire to change as much of possible of it to yellow plastic where it is not above ground and inspectable.
Not so long ago I dug up my concrete kitchen floor to find a gas pipe replaced by rust flakes and the gas retained by the pipe shaped outline in the floor slab. Only symptoms had been a slight smell of gas it you closed all the windows and wernt out for the day, and a floor that bubbled the soapy water up a bit when mopped. Made me wonder how many on other houses are like that but under lino.

-------------------------
regards Mike
 28 July 2017 04:03 PM
User is offline View Users Profile Print this message



ectophile

Posts: 746
Joined: 17 September 2001

That bit of pipe was bypassed when the gas company tried to pull a plastic liner along the pipe, as part of a local gas main re-lining exercise. The liner jammed somewhere under the house. The simplest solution was to stick a new meter box on the outside of the house, divert the incoming supply into that, then run a new pipe around the outside of the house and in through the wall.

So you're right - I have no idea what is the state of the pipe under the house.

-------------------------
S P Barker BSc PhD IEng MIET
 29 July 2017 10:01 AM
User is offline View Users Profile Print this message



ToniSM

Posts: 329
Joined: 21 November 2006

Originally posted by: ectophile

On the plus side, the lump of old pipe poking out of the floor of my meter cupboard isn't just a redundant bit of old gas pipe that nobody could be bothered to remove. Instead, it's an 18th edition earth electrode, already installed!


It works really well. I found an old gas pipe while digging a new drain, correction I found a new 600Ft long earth electrode.

-------------------------
Could there be a better way?

In theory yes, but in practice?
 29 July 2017 08:48 PM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 15811
Joined: 13 August 2003

correction I found a new 600Ft long earth electrode

Excellent- any chance you could loop test it for us and see what resistance you get? (OK not precise but should give us an idea - which we can then scale down to say a 40m foundation electrode...)
- Andy.
 29 July 2017 09:03 PM
User is offline View Users Profile Print this message



sparkingchip

Posts: 9953
Joined: 18 January 2003

Originally posted by: AJJewsbury

correction I found a new 600Ft long earth electrode


Excellent- any chance you could loop test it for us and see what resistance you get? (OK not precise but should give us an idea - which we can then scale down to say a 40m foundation electrode...)

- Andy.



It will be possible to work in reverse and determine the maximum kilowatt loading it is safe to use without risking a "dangerous" touch voltage if you have a TNCS supply and the PEN fails. I wonder if you are loading your installation within safe limits?

Can we as electricians and designers install a label on a consumer unit stating the maximum safe loading of an installation in kilowatts and/ or amps to stay within safe touch voltage limits if a PEN fails?

I have started a discussion with an example of a installation in the hope of getting some positive input on earthing the DNO earth terminal.

Andy B.
 30 July 2017 10:48 AM
User is offline View Users Profile Print this message



Zoomup

Posts: 3265
Joined: 20 February 2014

"Can we as electricians and designers install a label on a consumer unit stating the maximum safe loading of an installation in kilowatts and/ or amps to stay within safe touch voltage limits if a PEN fails? " Is that really our job Andy? I am not going along with that. It is up to the local distributor to legally ensure the safety of an installation and its main earth terminal earthing arrangement. The users of the installation would not read any such label, or if they did so would not fully understand its wording anyway in most cases. It is a silly idea to assume that wet or dry garden or road dirt can carry any reasonable amount of current at low Voltage. Expecting soil to reliably carry any reasonable amount of electric current is a misnomer. The whole idea of reliable low Voltage soil earthing is a fallacy like believing in a flat earth.


Z.
 06 August 2017 10:22 AM
User is offline View Users Profile Print this message



basil.wallace

Posts: 239
Joined: 01 April 2006

Originally posted by: spinlondon

I don't think it's a matter of being rushed through.

More like restricting the number of comments that they will have to ignore.


One comment I did make is that there don't seem to be any mention of Type2+3 SPDs protecting LED outdoor luminaires (street-light) in the Draft BS7671. The regulations only talks about consideration which is rather vague.

Basil Wallace PgDip MIET EngTech
 23 August 2017 02:23 AM
User is offline View Users Profile Print this message



mapj1

Posts: 9346
Joined: 22 July 2004

Last chance to comment chaps and chapesses - the shutters come down sometime in the next 24 hours.

-------------------------
regards Mike
 23 August 2017 12:14 PM
User is offline View Users Profile Print this message



sparkingchip

Posts: 9953
Joined: 18 January 2003

I think my comment that the requirements for all installations to have an earth rod will be discounted as saying it is ridiculous will not be deemed to be constructive.

However I left it at that, because it really should not need a local jobbing electrician to explain the feasibility of this proposal to the committee.

Andrew Betteridge
 23 August 2017 12:27 PM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 15811
Joined: 13 August 2003

However I left it at that, because it really should not need a local jobbing electrician to explain the feasibility of this proposal to the committee.

All wizards should have a hobbit or two in their care - to teach them the meaning of the world, and to correct them.

- Andy.
 23 August 2017 06:02 PM
User is offline View Users Profile Print this message



mapj1

Posts: 9346
Joined: 22 July 2004

I think my comment that the requirements for all installations to have an earth rod will be discounted as saying it is ridiculous will not be deemed to be constructive.


Well, you are not alone, I said much the same thing, albeit in two paragraphs, recommending either the deletion of the clause or its replacement with one explaining why TNC-s supplies were unsuitable for continued use...
Actually , I think I can see your comment in the log..

-------------------------
regards Mike
IET » Wiring and the regulations » 18th EDITION DPC

<< 9 10 11 12 Previous Last unread
Topic Tools Topic Tools
Statistics

New here?


See Also:



FuseTalk Standard Edition v3.2 - © 1999-2017 FuseTalk Inc. All rights reserved.

..