IET logo
 
IET
Decrease font size
Increase font size
Topic Title: Earth clamp on incoming mains
Topic Summary: Elec company says o k ?
Created On: 21 February 2009 07:12 PM
Status: Post and Reply
Linear : Threading : Single : Branch
1 2 Next 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.
 21 February 2009 07:12 PM
User is offline View Users Profile Print this message



Ampman

Posts: 1030
Joined: 06 February 2006

Evening all

Doing some refurb work in an house ,

When i first looked at job noticed mains intake was TNS with use of clamp on the cable ( lead )

Asked owner of house to get electricity board in to install a double pole isolater and install PME ( TNCS )connection .

First day on job today double pole isolater fitted no PME connection .

Owner said electricity guy said this was OK .

Had a look in next doors property done the same .

This sort of setup is a big NO NO on SWA cables we use .

Do you guys know if elec board are allowed to do it ?

Also they have left all power of to the house Very strange ?

Owner needs to contact them to come and re-energise .

The cable is lead .

Cheers
 21 February 2009 07:25 PM
User is offline View Users Profile Print this message



daveparry1

Posts: 6335
Joined: 04 July 2007

Is this a BS951 clamp you're talking about?
You mentioned SWA,I think there's a lot of difference between having a BS951 on an SWA and on a lead sheathed suppliers cable, there are a lot of those about and an EDF chap I spoke to some time ago told me that's often what they're given to use,
regards,
Dave.
 21 February 2009 07:28 PM
User is offline View Users Profile Print this message


Avatar for mitten.
mitten

Posts: 382
Joined: 29 January 2009

can't remember seeing anything thing else other that an earth clamp round incoming lead cable

-------------------------
Jason
 21 February 2009 07:30 PM
User is offline View Users Profile Print this message



Phillron

Posts: 1243
Joined: 18 January 2007

What sort of clamp are you refering to ?
When you say a big no no,is it a bog standard earth bonding compression type clamp EC15 or EC16 ?

What reading has been obtained for the existing TNS ?

What is unsatisfactory with the TNS to seek a TNC-S ?
 21 February 2009 07:52 PM
User is offline View Users Profile Print this message



Ampman

Posts: 1030
Joined: 06 February 2006

It looks like a EC15.

No reading taken as of yet .

Could someone please explain the difference betwwen an ec 15 & a 951 clamp .

Many thanks .

Just bothers me as we always told not to use clamps on cables due to the lead shrinking due to heat conditions which will in turn loosen the clamp .

cheers
 21 February 2009 08:02 PM
User is offline View Users Profile Print this message


Avatar for mitten.
mitten

Posts: 382
Joined: 29 January 2009

same thing it is an earth clamp ec15 or ec16 to bs951

-------------------------
Jason
 21 February 2009 08:29 PM
User is offline View Users Profile Print this message



Phillron

Posts: 1243
Joined: 18 January 2007

EC 15/16 clamps are not designed with clamping a lead sheath cable in mind
As you are aware they rely on compression to make a satisfactory contact
They are in situ in quite a number of installs that I have seen over the years,probably put on by the spark working on the installation
I would never dream of doing this,because the lead being a soft metal will tend to crush,I would have to have my eyes closed waiting for the tell tale bang
 21 February 2009 08:34 PM
User is offline View Users Profile Print this message


Avatar for mitten.
mitten

Posts: 382
Joined: 29 January 2009

I know what your saying ,but how many have you seen or heard of going bang?

-------------------------
Jason
 21 February 2009 08:38 PM
User is offline View Users Profile Print this message



Phillron

Posts: 1243
Joined: 18 January 2007

My answer None
but, an apprentice I was told that you could hit a lenghth of pyro with a sledge hammer and it would survive,but I never tried that one either
 21 February 2009 08:42 PM
User is offline View Users Profile Print this message


Avatar for mitten.
mitten

Posts: 382
Joined: 29 January 2009

Originally posted by: Phillron

My answer None

but, an apprentice I was told that you could hit a lenghth of pyro with a sledge hammer and it would survive,but I never tried that one either


As a young lad i was told that if you ram a pencil up your back side it does'nt hurt but have never tried it!
Just press on

-------------------------
Jason
 21 February 2009 08:53 PM
User is offline View Users Profile Print this message



Phillron

Posts: 1243
Joined: 18 January 2007

As a young lad i was told that if you ram a pencil up your back side it does'nt hurt but have never tried it!

Just press on


If someone was doing that, then I suppose it would help them to write a load of s--e for the screwfix forum

Edited: 21 February 2009 at 08:54 PM by Phillron
 21 February 2009 08:59 PM
User is offline View Users Profile Print this message


Avatar for Inrush.
Inrush

Posts: 710
Joined: 19 December 2007

http://www.theiet.org/forums/f...keyword1=earth%20clamp

See these posts for more info on this subject
 21 February 2009 09:43 PM
User is offline View Users Profile Print this message



peteTLM

Posts: 3217
Joined: 31 March 2005

blimey, how many of those users have been deleted!!!

P

-------------------------
----------------------------------------
Lack of planning on your part doesn't make it an emergency on mine....

Every man has to know his limitations- Dirty Harry
 21 February 2009 09:50 PM
User is offline View Users Profile Print this message


Avatar for Inrush.
Inrush

Posts: 710
Joined: 19 December 2007

blimey, how many of those users have been deleted!!!


That's what happens when you install a BS951 earthing clamp on the lead sheath of a DNO cable I guess
 21 February 2009 10:08 PM
User is offline View Users Profile Print this message



John Peckham

Posts: 7580
Joined: 23 April 2005

951 clamps were fitted by EDF, and the companies they absorbed, by the million. I saw a brand new one fitted by an EDF contractor 2 years ago. If you get a satisfactory Zs don't worry. Now days they fit a constant pressure spring and a braided earth to an MET. The suppliers cable belongs to the supplier and should not be interfered with by unauthorised people. Also BS7671 does not apply to suppliers equipment.

-------------------------
John Peckham

http://www.astutetechnicalservices.co.uk/
 22 February 2009 09:28 AM
User is offline View Users Profile Print this message


Avatar for Inrush.
Inrush

Posts: 710
Joined: 19 December 2007

Also BS7671 does not apply to suppliers equipment.


I know a couple of guys who are engineers in a power station, they tell me that they have 'good working guides' for all circuits /modifications etc but they don't work to BS7671 .

One of these guys was doing his 17th edition last week, I spoke to him beforehand and he wasn't looking forward to it (his manager wants to make them aware of the regulations in the real world apparently).

Edited: 22 February 2009 at 09:28 AM by Inrush
 22 February 2009 09:38 AM
User is offline View Users Profile Print this message



alancapon

Posts: 5812
Joined: 27 December 2005

Originally posted by: Inrush
I know a couple of guys who are engineers in a power station, they tell me that they have 'good working guides' for all circuits /modifications etc but they don't work to BS7671.


That has been the case for many years, and is included in part 110.2 as an exception in BS7671:2008. There are many examples on the electricity generation / transmission / distribution network, where BS7671 does not fit, and cannot be applied. In virtually all cases, there are other regulations which go above and beyond what BS7671 would require anyway. In cases where BS7671 is applied, the other relevent regulations are still applied too.


Regards,

Alan.
 22 February 2009 10:05 AM
User is offline View Users Profile Print this message


Avatar for Inrush.
Inrush

Posts: 710
Joined: 19 December 2007

There are many examples on the electricity generation / transmission / distribution network, where BS7671 does not fit, and cannot be applied. In virtually all cases, there are other regulations which go above and beyond what BS7671 would require anyway.


I was aiming this more at the domestic circuits inside the station, such as power for canteen lights ring circuits etc.
 22 February 2009 05:01 PM
User is offline View Users Profile Print this message



kaichung

Posts: 370
Joined: 02 December 2003

What's all the fuss all about, just go on and put a BS951 tenby clamp on the incoming cable, and use a Power Driver to tighten it really well, manual screwdrivers cannot tighten them up hard enough, and leave it there. The cable is not going to be damaged - have YOU ever encountered a damaged incomer cable in these circumstances?
 22 February 2009 05:01 PM
User is offline View Users Profile Print this message



kaichung

Posts: 370
Joined: 02 December 2003

What's all the fuss all about, just go on and put a BS951 tenby clamp on the incoming cable, and use a Power Driver to tighten it really well, manual screwdrivers cannot tighten them up hard enough, and leave it there. The cable is not going to be damaged - have YOU ever encountered a damaged incomer cable in these circumstances?
IET » Wiring and the regulations » Earth clamp on incoming mains

1 2 Next Last unread
Topic Tools Topic Tools
Statistics

See Also:



FuseTalk Standard Edition v3.2 - © 1999-2014 FuseTalk Inc. All rights reserved.