Dno Earth Appears Too Small...

[golfpaul]

Hi all.

Job is for extra sockets in kitchen, will be surface run with rcd fronts, as no rcd at CCU.

The setup is fairly old, and the incoming tns earth looks woefully underrated - I will be upgrading the main bonding also, as this is also too small.

Should i advise the DNO before i start, or do they know something I (we) dont?

Cheers.

 

[NozSpark]

Which regs do you think that the DNO work to??

 

[golfpaul]

Not Bs7671.

But it visually looks too small.

 

[Blue Duck]

They don't give a brass monkey.

what's the external impedance like?

what's the head like?

you might be able to get the head changed under a "dangerous situation" if it cast iron or leaky

 

[golfpaul]

Not done any tests yet BlueDuck, going tomorrow - it may well be ok, but really did 'look' underrated.

So as long as the tests are satisfactory, and i upgrade the consumers side main bonding, I shouldnt worry?

 

[binky]

post a piccy

 

[ProDave]

DNO's work to their own rules.

How they deal with faults or upgrades varies tremendously with region, and can be compounded if the energy supplier is not the DNO and the DNO will direct your request to the energy supplier who usually don't understand or don't give a flying fig.

I tried to get some under sized tails upgraded recently, all that met with was a "supply upgrade" request form to fill in. No I don't want the supply upgraded, I just want it fixed so it can safely supply what it's supposed to supply.

In this case it was to add an electric shower.  Sometimes you get a better response if you add the new load (new shower) then call them as an emergency when the under sized tails are getting hot.

 

[Blue Duck]

tails are mostly the responsibility of the supplier and sometimes the fuse.

I find the DNO to be much more helpful though they won't come out and fit a new earth / clamp. if the readings are ok then you could always get the head upgraded or get it PME'd.

or just make a note of it and move on...

 

[SLIPSHOD & SLAPDASH]

Most old Tns round my way have an earth of about 3mm sweated on.Then in the late 70s to early 80s Eastern electric fitted 951 clamps to the sheath with 6mm attached and have spent the last 30 years denying it.

 

[NozSpark]

TNS are the same here,,, but they then went to perforated band placed under a 2 way earth block

and if I find a 951 clamp then they will deny all knowledge of it and make you TT it

 

[golfpaul]

Also...

No MET, can i install one from the incoming, then then onto the main bonding and CCU...

Sorry for the basics, not worked on many old installs with this kinda setup.

Thanks in advance  :Blushing

 

[Blue Duck]

Went to this job yesterday,

Loads of problems but last week I took a zs on a socket that was to be moved and it was too high even for a TT.

As you can see in the first pic there is no main earth and in the bottom RH corner there are tails going to a 17th ed board! headbang

Also someone had the bright idea of building a wardrobe over the lot!

Removed wardrobe and called UKPN, No main earth yada yada yada, can't do anything yada yada yada. come change the head then its a bit old :lol:

Put your own MET in near the head in a convenient place they still may not use it

No PME available in N16