Bear with me on this one

[cliffed]

So if you supply a external lamp post(metal),the metal is an exposed conductive part,& connected to the cpc,no main bonding required.
If you add a socket or a light to an external remote metal shed,will this need main bonding,or the cpc on the power point or light will suffice.
It’s an actual aleady extraneous part,with its structure embedded to earth.

 

[telectrix]

metal shed will need TT earthing if supply is PME.

 

[Dustydazzler]

Exporting pme and alll thattt jazzzz

 

[cliffed]

metal shed will need TT earthing if supply is PME.

Thanks exactly what I thought,so by putting a power point in,they will now need,either the main bonding extended,or for ease a DB with Rcd tt system ,then main bonding locally.
They will have a fit.

 

[Ian1981]

If a shed is an extraneous conductive part with electrical accessories and wiring installed then no the cpc on a light or socket will not do at all regarding satisfactory protective bonding, how the hell would it?

 

[Ian1981]

So if you supply a external lamp post(metal),the metal is an exposed conductive part,& connected to the cpc,no main bonding required.
If you add a socket or a light to an external remote metal shed,will this need main bonding,or the cpc on the power point or light will suffice.
It’s an actual aleady extraneous part,with its structure embedded to earth.

An external lamppost will be classed as an exposed conductive part, if it was to introduce an earth potential then to provide protective bonding to it is pointless and unnecessary as it’s located directly outside, so you could never maintain or create an equipotential bonding zone being directly stood on the ground and all.

 

[westward10]

When I was a member of the ILE a debate took place as to whether the column of a lamp post could serve as an electrode for the purpose of staking PME supplies. The suggestion was no because most columns are treated at low level to prevent corrosion and as such may not be effective.

 

[cliffed]

An external lamppost will be classed as an exposed conductive part, if it was to introduce an earth potential then to provide protective bonding to it is pointless and unnecessary as it’s located directly outside, so you could never maintain or create an equipotential bonding zone being directly stood on the ground and all.

Understand,so does the shed need Main bonding,it’s more like an open porch than a shed ie: no doors,just frame work.
It’s external,& like you said being stood on the ground outside.
Would that be referenced as a true earth,unlike extraneous conductive parts,which may introduce a potential.

 

[cliffed]

If a shed is an extraneous conductive part with electrical accessories and wiring installed then no the cpc on a light or socket will not do at all regarding satisfactory protective bonding, how the hell would it?

Is it extraneous ,it’s outside.

 

[Ian1981]

Is it extraneous ,it’s outside.

Does not mean that it’s an extraneous conductive part and will introduce an earth potential, if it’s foundations are imbedded deep enough into the ground then yes it would require bonding

 

[Deleted member 26818]

When I was younger, I used to install lamp posts.
In order to be able to connect to the REC PME earth connection, we had to install an earth electrode (usually at the penultimate column).
Depending upon which REC we were dealing with, determined how low our RA had to be.
South Eastern, just wanted an electrode, the LEB wanted an RA of 10 Ohms.

 

[cliffed]

Yea,can understand all these comments,we didn’t fit the socket,it’s on an industrial estate,the main supply is a 1,200 amp Pme system,so definitely an earth potential there.
The actual main bonding conductor is 50mm.

 

[Zerax]

When I was younger, I used to install lamp posts.
In order to be able to connect to the REC PME earth connection, we had to install an earth electrode (usually at the penultimate column).
Depending upon which REC we were dealing with, determined how low our RA had to be.
South Eastern, just wanted an electrode, the LEB wanted an RA of 10 Ohms.

Why would you need an earth connection with a gas lamp ??

 

[cliffed]

Exactly,ha ha

 

[Deleted member 26818]

You do realise, it was during the Napoleonic wars that they first installed electric lamp posts in London?

 

[ChrisElectrical88]

When I was younger, I used to install lamp posts.
In order to be able to connect to the REC PME earth connection, we had to install an earth electrode (usually at the penultimate column).
Depending upon which REC we were dealing with, determined how low our RA had to be.
South Eastern, just wanted an electrode, the LEB wanted an RA of 10 Ohms.

This would have been concrete columns?

 

[telectrix]

You do realise, it was during the Napoleonic wars that they first installed electric lamp posts in London?

wrong. napoleon was defeated in 1815. London first got electric streetlights late in the century.

 

[andyb]

You do realise, it was during the Napoleonic wars that they first installed electric lamp posts in London?

Don't think that can be true Spin.
The napoleonic wars were late 18th early 19th centuary.
Edison was later in the 19th.

 

[Deleted member 26818]

Sorry, it was gas lamps that were put up during the Napoleonic wars.
Electric lamps didn’t come along until 50 odd years later.

 

[Dave OCD]

I'd say it's standard spec throughout the country -certainly for L.A. 'adopted' street lighting that the column has a 10mm main bonding conductor connected to the MET, the steel columns all have a terminal near the door opening for this. I know that in Cornwall at least 95% of the supplies are PME and when you consider your average 8 or 10 metre column on busy routes has a 'planting depth' of between 1.2 and 1.5 metres it's not going to do the RECs ELI any harm eh ?