Supply Type

[dizz]

Can I ask what type of supply this is please?

Untitled

• dizz
• 7 Apr 2011
• 1

I have separate E7, so I guess two of the earth cables are going to the two CU's, the other two look like they are coming in separately from the DNO?

 

[mikhailfaradayski]

looks like a TN-C-S supply (aka PME)

 

[dizz]

ah -the metal strip on the right says "Protective Multiple Earth" - It has to be TN-C-S then? How come two earths coming in?

 

[Taylortwocities]

How come two earths coming in?

There is NO earth coming IN. The neutral conductor is also the earth (look up TN-C-S).

All those earths are out to something.

One to 24 CU
one to E7 CU
The others probably bonding to water/gas/oil etc??

It is not unusual for the bonding to be connected at the intake.

I do not like that practice as the only way to access the conductors (for verification) is to break the DNO's seal, and they don't like that.

 

[Wontdothatagain]

I do not like that practice as the only way to access the conductors (for verification) is to break the DNO's seal, and they don't like that.

The picture does not show it well but there are 2 "knock outs" on the PME cover. It is designed for an electrician to be able to gain access without removing the fuse and to connect an approipreat sized main earth from the head to a MET block.

 

[dizz]

Ok - So it is a TNCS? - Is that because you cannot see a separate earth coming into the building, and therefore it comes from the N from that grey block where the FOUR Earths exit?

 

[aptsys]

Two of them might not be 'earths'

 

[Taylortwocities]

Two of them might not be 'earths'

Don't start that, again. Its boring.

Lets call them protective conductors, shall we?

 

[aptsys]

View media item 32954
Can't say I've ever seen them all connected at the MET though - there's not usually enough terminals.

 

[dizz]

DNO confirmed today it is a PME supply - thanks.

 

[Taylortwocities]

Don't know why you bothered to ask. Surely there was no confusion just by looking at the supply head.
Also - as you spotted

ah -the metal strip on the right says "Protective Multiple Earth" - It has to be TN-C-S then?

 

[dizz]

Don't know why you bothered to ask. Surely there was no confusion just by looking at the supply head.
Also - as you spotted

ah -the metal strip on the right says "Protective Multiple Earth" - It has to be TN-C-S then?

Easy for you to say - I didn't know what PME meant in terms of TNCS, but it's been explained to me. I asked because when I raised the query with the DNO, they said it woud take two weeks to get the to premises, but in fact, I got a call this morning and he arrived today.

 

[Chri5]

Dizz that is so basic that you worry me. Surely knowing earthing types is as fundamental as you can get.

It's comparative would be an accountant that doesn't know maths !

 

[ColJack]

I've been away, but does Dizz claim to be an electrician?

he sounds like a homeowner to me trying to learn about his installation..

that's more akin to you trying to do your own accounts and not knowing what a certain tax code means..