Earth Bonding was not done. Need help.

[Temas]

Ps - What is the Switchplate (?) or Blank to the Right-hand side of the Window ??

It was a light switch, before the room was turned into a bathroom. There are taped up switch cables inside. I can't remember exactly why it wasn't tiled over. I seem to recall the builder saying it could be useful to leave it there incase I needed to an outlet for anything in the future.

 

[Luckyphil]

So if you read my Posting ( and Sparkybirds copy ) you`ll see there are ways round this with minimal mess , speak to the Sparky who quoted for the Fan about the Works , at the same time he may be able to pull out those redundant Cables behind that Blanking Plate.

Lucky

 

[riveralt]

You should have the Equipotential Bonding installed /upgraded to the incoming services within 600mm of the Stopcock where practicable,(Gas/Water) in 10mm G/Y Cable.

Note Supplementary Bonding & Equipotential Bonding are not the same thing

To avoid confusion the terms now used in BS7671 are:

Main protective bonding - of metal services - gas water oil etc.
Supplementary equipotential bonding of metal surfaces in certain specific locations such as kitchens and bathrooms.

The location of the RCD as suggested by LuckyPhil and Sparkybird is fine if you have a TNCS or TNS earthing system but not if you have a TT system.

 

[ricicle]

The location of the RCD as suggested by LuckyPhil and Sparkybird is fine if you have a TNCS or TNS earthing system but not if you have a TT system.

Please expand ?

 

[riveralt]

The location of the RCD as suggested by LuckyPhil and Sparkybird is fine if you have a TNCS or TNS earthing system but not if you have a TT system.

Please expand ?

Which bit?

 

[ricicle]

On the reason for that statement with regard to the RCD location and it's influence by the earthing system.

 

[riveralt]

On the reason for that statement with regard to the RCD location and it's influence by the earthing system.

We don't know what earthing system, if any, is in place in this property.
The photographs show an old wylex board with push in push button mcb's and a single earth cable leaving at the top toward what we have been told is the central heating pipes - So on face value there appears to be no main protective bonding at the main earth terminal nor indeed any photographic evidence of a main earthing cable.

My view is that the issue of supplementary equipotential bonding is secondary to the earthing system and the main protective bonding. If it does exist and it is TN - which meets ADS, without RCD protection at CU and all extraneous conductive parts of the location are effectively connected to the main protective bonding then positioning the RCD at the location suggested seems fine to me since it meets the three criteria highlighted in the BRB 701.425.2.
However, if the main earthing system is not present or is TT based then this should already be protected by an RCD to meet 411.3.2.and the introduction of a secondary RCD is unecessary and may cause discrimination issues.

 

[ban-all-sheds]

I seem to recall the builder saying it could be useful to leave it there incase I needed to an outlet for anything in the future.

 

[Luckyphil]

Builders ......... don`t ya just love Em

Jack of all Trades ............ fill in the Rest !!!


Lucky

 

[Luckyphil]

Temas , can you post a Piccy of your Meter and the Main Fuse (where the Large Cables go from the Consumer Unit) and where the incoming Supply Cables to the Main Fuse are ?

Is this a Flat or a House BTW

Regards

Lucky

Ps - Is the large cable at the bottom of the Consumer unit RHS the incoming Feed to the Property ? or a Cooker supply Cable or ???

 

[ricicle]

On the reason for that statement with regard to the RCD location and it's influence by the earthing system.

We don't know what earthing system, if any, is in place in this property.
The photographs show an old wylex board with push in push button mcb's and a single earth cable leaving at the top toward what we have been told is the central heating pipes - So on face value there appears to be no main protective bonding at the main earth terminal nor indeed any photographic evidence of a main earthing cable.

My view is that the issue of supplementary equipotential bonding is secondary to the earthing system and the main protective bonding. If it does exist and it is TN - which meets ADS, without RCD protection at CU and all extraneous conductive parts of the location are effectively connected to the main protective bonding then positioning the RCD at the location suggested seems fine to me since it meets the three criteria highlighted in the BRB 701.425.2.
However, if the main earthing system is not present or is TT based then this should already be protected by an RCD to meet 411.3.2.and the introduction of a secondary RCD is unecessary and may cause discrimination issues.

That's a lot of speculation ! Let's hope it's not a TT unless there is an out of view front end RCD due to the metalclad CU. There is a school of thought that suggests an RCD on a bathroom circuit should protect the whole circuit not just the part in the bathroom. (Imagine an earth fault on the lighting circuit just outside the bathroom which would not cause RCD operation)

 

[ban-all-sheds]

There is a school of thought that suggests an RCD on a bathroom circuit should protect the whole circuit not just the part in the bathroom.

Indeed - the wording is circuits of the location, not in....

(Imagine an earth fault on the lighting circuit just outside the bathroom which would not cause RCD operation)

Indeed #2. Your bathroom contains exposed and extraneous conductive parts. You have no supplementary equipotential bonding. You have a fault upstream of your local RCD which has raised the potential of an extraneous conductive part with respect to the exposed ones to a dangerous level.

This is a Bad Thing™.

 

[dhutch]

IMHO the easiest thing would be to RCD protect bathroom circuit so doing away with the need to supplementary bonding. This assumes main bonding to incoming gas and water pipes is in place.

Im not an electrician, but rather than trying to retrospectivly add protection to the bathroom alone would it not be easier to add it to the whole house by replacing the CU which would intern improve the protection to the rest of the house?


Daniel

 

[mikhailfaradayski]

IMHO the easiest thing would be to RCD protect bathroom circuit so doing away with the need to supplementary bonding. This assumes main bonding to incoming gas and water pipes is in place.

Im not an electrician, but rather than trying to retrospectivly add protection to the bathroom alone would it not be easier to add it to the whole house by replacing the CU which would intern improve the protection to the rest of the house?


Daniel

-Easier, mmm, possibly.
-Necessary, no.
-More expensive, yes, probably by a few hundred quid