If you have 2 completly seperate supplys, both TT and they are right next to each other, is it exceptable for them to be both of the same earth rod???
TT supply
- Thread starter Wontdothatagain
- Start date
Sponsored Links
My house was originally 2 flats ( concentric o/head supply) and both used the same rod.
I havent looked it up but from a pure common sense point of view the answer is no. What happens what one supply is being worked on and someone needs to do any work / tests on the rod. They may have to disconnect the earth to the other supply as well.
The property in question is a shop on the ground floor and flat above. 2 completly seperate supplys. Both meters are in the shop and in the same cupboard next to each other.
At the moment, there is
no main bond to the gas meter
no main bond to water supply
No RCD protection, straight from service fuse to 60A isolator, to DB
1 existing earth rod, hammered into the ground and a piece of 2.5mm green, soldered to the rod going to flat isolator. The green cable has been twisted to the CPC of the 16mm T&E coming out of the isolator
shop DB has nothing.
The 1 eart rod is inside directly under the servise fuses in nice dry ground.
The whole install is a complete mess and i have not tested anything as i did not want to touch any part of it until i could isolate the lot whitch the customer would not let me do
At the moment, there is
no main bond to the gas meter
no main bond to water supply
No RCD protection, straight from service fuse to 60A isolator, to DB
1 existing earth rod, hammered into the ground and a piece of 2.5mm green, soldered to the rod going to flat isolator. The green cable has been twisted to the CPC of the 16mm T&E coming out of the isolator
shop DB has nothing.
The 1 eart rod is inside directly under the servise fuses in nice dry ground.
The whole install is a complete mess and i have not tested anything as i did not want to touch any part of it until i could isolate the lot whitch the customer would not let me do
Sponsored Links
TN installations all use the same earth electrode - that of the source.
In principle it would be the same for two installations using a common earth electrode, although each would have its own earthing conductor.
The code of practice for earthing, BS 7430, would need to be consulted and possibly the DNO. But most importantly, with joint responsibility to maintain the means of earthing, both installation owners would have to agree on the type of earth electrode and arrange unfettered mutual access for maintenance purposes.
Of course, as BSBS has pointed out, what if, at some future date there are occasions when testing has to be carried out that involves the disconnection of the earth electrode when it is inconvenient for one or other installation to be de-energised? On the other hand, separate electrodes may simply not be practical, due to overlapping zones of influence, etc.
Best to ask the experts: http://www.furse.com
In principle it would be the same for two installations using a common earth electrode, although each would have its own earthing conductor.
The code of practice for earthing, BS 7430, would need to be consulted and possibly the DNO. But most importantly, with joint responsibility to maintain the means of earthing, both installation owners would have to agree on the type of earth electrode and arrange unfettered mutual access for maintenance purposes.
Of course, as BSBS has pointed out, what if, at some future date there are occasions when testing has to be carried out that involves the disconnection of the earth electrode when it is inconvenient for one or other installation to be de-energised? On the other hand, separate electrodes may simply not be practical, due to overlapping zones of influence, etc.
Best to ask the experts: http://www.furse.com
Thanks all. Think i will just put 2 rods in. What i was thinking of doing was fitting 2 rod clamps on the 1 rod but because the rod is inside and most probably will not give a good reading, i will fit 2 new rods outside. Problem is i have to drill through a 3 feet thick stone wall to get outside 
need to get a new clutch on me Bosch before i use one of them
You'll push a 10mm through easy enough unless of course it's damp stome, and then you'll struggle like a right t--t, just like I did yesterday.
Drained 3 batteries on my 24V makita just doing one 12mm hole through a ~60mm thick wall.
Drained 3 batteries on my 24V makita just doing one 12mm hole through a ~60mm thick wall.
Drained 3 batteries on my 24V makita just doing one 12mm hole through a ~60mm thick wall.
Think I'd have got the 110v sds from the van after it still seemed hard going after draining one battery
Are you aware that the code of practice says you should discount the first metre of buried rod? That is, a one-metre rod is not considered to give reliably low and maintainably stable readings. Also, separate rods need to be spaced sufficiently far apart that they do not influence each other - and that will depend on their depths, soil resistivity, type and cross-sectional shape and area of the rod/s, etc.
Relative to everything else an electrician encounters, the business of earthing is complex. It is not as simple as whacking in a rod, peeing on it and taking a Ze measurement, as many seem to think. So, do some reading up and go prepared - Guidance Note 8 (which should be in every electrician's library) is a good start.
dingbat";p="1787089 said:
- Joined
- 11 Jan 2004
- Messages
- 42,733
- Reaction score
- 2,633
- Country
I think he meant to quote:
No, I agree, it's not that simple. Sometimes you have to pee on it twice...
No, I agree, it's not that simple. Sometimes you have to pee on it twice...
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
