Power point in external glasshouse

[Julie.]

In many cases we’ve been told that supplying a remote garage from a Tncs supply a 10mm bonding must be installed if there are extraneous conductive parts in that area.
In many cases the easiest option would be to convert to a TT System & install a 6.0 mm

Why TT, just run a 1.5mm^2 swa including the armour as CPC and bonding and it meets the regs.

Cheapest option

 

[westward10]

No, it's not the MPBC, it's extraneous conductive part in a remote building therefore the bonding size is dependent upon the circuit to that building.

I have heard of this new Reg but not perused it does it apply to all TN systems.

 

[Julie.]

I have heard of this new Reg but not perused it does it apply to all TN systems.

Yes, it basically means you don't need to size the extraneous conductive part bonding on the incoming supply, but on the supply to the particular building with a minimum of 6mm^2

The rest is the same other than a bit of clarification on what is extraneous - ie not just where a bit of metal passes through the wall!

 

[Julie.]

I think it's poor wording though, it uses "main protective bonding conductor" to mean both the main protective bonding conductor at the incomer (which is based of the incomer size), and for the remote building.

I think "main protective bonding conductor" should be reserved for the incoming aspect and something like "remote building protective conductor " for the remote building.

Just to distinguish between them or else there will be confusion, 'when I say the main protective bonding conductor, I don't mean the main one, I mean one of the other main ones....'

 

[cliffed]

I have heard of this new Reg but not perused it does it apply to all TN systems.

This is new to me too is the reg present in the latest amendment books

 

[cliffed]

This is what I found & only on non Pme supplies

 

[loz2754]

This is what I found & only on non Pme supplies

See post number 15

 

[Julie.]

This is new to me too is the reg present in the latest amendment books

Yes, it is in the current standard (18th edition amd 2.)

We can only follow the old standard (amd 1) for up to 6 months,

 

[mainline]

Client wants 2g socket in greenhouse, obviously IP rated,will be supplied from Rcd, the greenhouse consists of metal frame work on the ground.
Does this require MPBC

How far away is the greenhouse
Are you planning on using swa ?

 

[cliffed]

How far away is the greenhouse
Are you planning on using swa ?

There’s a duct into the greenhouse, which comes from a external power point, so maybe rubber cabling

 

[cliffed]

Why TT, just run a 1.5mm^2 swa including the armour as CPC and bonding and it meets the regs.

Cheapest option

Except Pme supplies

 

[westward10]

If that is the new book I did wonder if it applied to all TN systems.

 

[cliffed]

If that is the new book I did wonder if it applied to all TN systems.

It’s in the new book but without looking @ the blue book I’m pretty sure it’s in there too.

 

[cliffed]

I doubt if I would take a Pme supply to the greenhouse anyway.
It just highlights the requirements & the expense, if done correctly the costs of adding a Power point

 

[westward10]

It’s in the new book but without looking @ the blue book I’m pretty sure it’s in there too.

It is there but is now amended.

 

[cliffed]

It is there but is now amended.

Cheers…can’t get to my book yet…having a new bathroom fitted, the house upside down @ the moment

 

[Julie.]

Except Pme suppliesView attachment 96674

No not except PME, it is except where PME conditions apply.


You should not be applying PME as the CNE will have been split at the header into L, N & E. You should never combine the N & E within the installation.


The note re except where PME conditions apply, was there over several versions of the regs, we would still apply the 50% or min 10mm^2 rule.

In fact there is no sizing for bonding within the (wiring) regulations where PME does apply!

This is usually determined by the utility themselves, and is often 50% or min 16mm^2 for customer service points, and generally 32mm^2 within the network (eg SNE sheath to CNE) even if its to one customer.

 

[cliffed]

No not except PME, it is except where PME conditions apply.


You should not be applying PME as the CNE will have been split at the header into L, N & E. You should never combine the N & E within the installation.


The note re except where PME conditions apply, was there over several versions of the regs, we would still apply the 50% or min 10mm^2 rule.

In fact there is no sizing for bonding within the (wiring) regulations where PME does apply!

This is usually determined by the utility themselves, and is often 50% or min 16mm^2 for customer service points, and generally 32mm^2 within the network (eg SNE sheath to CNE) even if its to one customer.

I don’t intend to combine N & E..never have…For me it’s gonna be a TT system @ the greenhouse.
Also the 10mm MPBC would apply if using the DNO earth

 

[westward10]

This has become somewhat confused I asked in #22 if this applied to all TN systems and whilst TN-C-S does not necessarily mean PME I was answered yes it does but it doesn't?

 

[cliffed]

This has become somewhat confused I asked in #22 if this applied to all TN systems and whilst TN-C-S does not necessarily mean PME I was answered yes it does but it doesn't?

Definitely not apply to TNS