Main earth query on my rented home

[Loki]

Hi everyone,

Just wanted to confirm my suspicions about my rented homes pme main earth setup.

From the Dno (pme) the 16mm main earth connects to the gas & then on to the CU. The cable continuous.

CU was installed 10 years ago by a niceic registered electrician.

16mm tails.

Normally i know that main earth would go to MET & then to CU or straight to CU with gas bonded separately via 10mm.

Is the way its done against the 17th regs? Cant seem to find anything about this type of setup.

It looks like it was done because it was the easy option.

Suspecting it will need sorting but just wanted to confirm first as ive not come across this before.



Thanks in advance


Michael

 

[Pete999]

Hi everyone,

Just wanted to confirm my suspicions about my rented homes pme main earth setup.

From the Dno (pme) the 16mm main earth connects to the gas & then on to the CU. The cable continuous.

CU was installed 10 years ago by a niceic registered electrician.

16mm tails.

Normally i know that main earth would go to MET & then to CU or straight to CU with gas bonded separately via 10mm.

Is the way its done against the 17th regs? Cant seem to find anything about this type of setup.

It looks like it was done because it was the easy option.

Suspecting it will need sorting but just wanted to confirm first as ive not come across this before.



Thanks in advance


Michael

Looks like the installer is getting his Earthing and Bonding mixed up

 

[Loki]

Earthing & bonding going to be a pain to sort due to routing.

Seal fairies been again as no isolator fitted either.

16mm tails? wonder what Amp fuse is fitted?

Might need to fit a 80A fuse cutout if fuse is 100A? might be lucky & have either a 60A or 80A in it.

https://www.screwfix.com/p/wylex-80a-domestic-switch-fuse-unit/3359j

£75.96 ouch.

 

[Richard Burns]

I think this could be acceptable, the problem would be that in a fault situation the fault current would flow from MET to gas and cause a greater volt drop than would usually be experienced and so raise the touch voltage at the point of fault, however the volt drop over a 16mm² cable will be minimal compared to the volt drop over the faulty circuit cpc so it could well be acceptable if there is a short run to the consumer unit and the Ze is reasonably high.
The 16mm² tails from service head to meter cannot be changed and presumably were installed correctly at the time (you hope!!) and so the fuse despite the labelling ought to be 80A or less.
If this is a standard domestic property then the demand is very unlikely to exceed the CCC of the tails even though we are not allowed to take this into consideration.
As the meter box is outside the building there is a low risk of a fire in the box causing a fire risk to the property and so the non combustible requirement may not apply, GN4 states that this is intended to apply to inside domestic premises and attached and nearby buildings.
If you do use non combustible then a somewhat cheaper alternative and slightly smaller (and harder to terminate) would be a lewden switch fuse.

 

[David Prosser]

WPD should come out and change the fuse if it's a 100A. They will also fit a double pole isolator if you ask when booking them.

 

[The Ghost]

It is recommended to (if you are chain bonding at least) to make it unbroken, can't quite tell from the pic if it is? Looks like the blue type of BS951 should have been used as the environment looks damp. There appears to be no clamp over the top of the earth cable which is usual on these clamps. You can get a Wylex isolator for around £25.00. Thing is are you proposing to change any of this??? It is rented right? You might be jumping in the deep end a bit there no?

 

[Loki]

Thank you for all your replies, great forum as always.

The cable is continuous.

The meter boxes/conditions have been like that since I moved in 18 months ago & hasnt got any worse.

Am tempted to check the DNO fuse size as there's no seal. (I do have safety gloves etc)

Landlord is happy for me to do electrical work as I have done some in the past at his other properties for him.

To minimise the routing issue I thought that I could cut the 16mm earth near the electric meter & fit a MET bar & then reconnecting earths (basically inserting a MET). The side thats connected to the gas pipe I was thinking of disconnecting from the clamp & placing some sort of mechanical protection over the bare copper core, thus basically making it a 16mm from CU to MET & 16mm from MET to DNO cutout. I could then easily run a 10mm earth from the gas pipe clamp to the MET as the two meter enclosures are right next to each other.

Hope that made sense lol.

 

[Richard Burns]

Doing what you describe would make no change to the electrical routing it would merely nominally shift the classification of the MET from the CU to the meter box and effectively you might be able to say the MET is actually the connection at the gas meter at the moment anyway.

Electrically it is fine, operationally it may, but probably doesn't, cause an issue with a greater level of shock if someone is touching the gas pipe and an exposed conductive part at the same time as a fault occurs.

 

[Loki]

Basically with the magic of Microsoft paint my current setup is:

& what I suggested to do is:

 

[davesparks]

Do you have a copy of the most recent landlords gas safety report?
If you do then what does it have to say about the routing of that 16mm via the pipe entry to the meter box? I ask because, as far as I know, it is not acceptable from a gas safety standpoint.

 

[Loki]

I do remember the gas bloke doing his yearly check. Not sure if Ive got the certificate or if hes given it to the landlord. Ill check when I get back.
Im driving to visit my grandma 300 miles away shortly. She fell over yesterday & broke her hip & is in hospital. Going to take my parents up.

 

[Richard Burns]

Effectively what you are doing is actually this, the same method but different physical layout.

It just shows that you are adding a short length of 10mm² to the existing arrangement, which, if anything, might make it worse, it will not however really change anything.
The only way to make a difference would be have the 16mm² from supply to CU and to run the 10mm² from the gas back to the CU. You can see that in all other cases the fault current will still travel along the cable from CU to gas (or new MET) and change the pd experienced during a fault. Just leave it as it is.
Hope all is well with your grandma.

 

[davesparks]

I do remember the gas bloke doing his yearly check. Not sure if Ive got the certificate or if hes given it to the landlord. Ill check when I get back.
Im driving to visit my grandma 300 miles away shortly. She fell over yesterday & broke her hip & is in hospital. Going to take my parents up.

The landlord should have their copy, there should be a copy left at the property and another retained by the gas safe operative.