Does it need it?

[Liam howe]

hi everyone,
I have got a job to do in a local hairdresser to change a consumer unit fed off an economy 7 meter.

My question is do you need to test and notify the works like you would in a domestic dwelling? Also is it mandatory that the incoming services of water/gas are bonded with 10mm earth.

I know this is the correct procedure for domestic installs but this is our first non domestic job and we want to get it right.
Thanks

 

[hightower]

10mm bonding is the correct procedure for domestic installs? First I heard of it.

 

[Liam howe]

10mm bonding is the correct procedure for domestic installs? First I heard of it.

Have you been living under a rock?

Of course if you use the adiabatic equation you could probably get away with 6mm but any good electrician will always use 10mm the cost difference is minimal.

 

[Octopus]

The only difference between domestic and commercial is part p

 

[Midwest]

The sizes for main protective bonding conductors are mentioned in reg 544.1. Size would depend on the supply and size of earthing conductor and/or neutral conductor.

I expect most domestic properties with a PME supply, it would be 10mm, but not necessarily. I guess that's what Hightower refers to.

Scope of Part P, is refered to in that document 1.3.2.(citation my green OSG). I think, I might be wrong, but the adiabetic question formula is used to calculate protective conductors.

 

[Midwest]

OP looking at Part P (2013) , it's possible a commercial installation might require notification, 'where shared metering is used', Scope 2.2 d).

Amazing what you can find out, while sat on your arse, twiddling your thumbs ;

https://www.gov.uk/government/uploa...achment_data/file/441872/BR_PDF_AD_P_2013.pdf

 

[hightower]

Have you been living under a rock?

Of course if you use the adiabatic equation you could probably get away with 6mm but any good electrician will always use 10mm the cost difference is minimal.

I'd argue the opposite, in that any good electrician will always figure out if 10mm is needed rather than just upgrading it for the sake of it. Okay, the cable may not cost much, but some bonding runs are a nightmare. From the calculations I've done over the past few years I've yet to encounter a house with a TT or TN-S supply that actually needs 10mm.

 

[DPG]

Agree with hightower. See if it is needed, especially if it's a complicated run. Daz.

 

[Midwest]

I thought the 'adiabatic is used for sizing of the earth conductor and protective conductors, not bonding conductors.
Bonding conductor sizes are selected from the calculated (or selected using tables) size of earth conductor or protective conductor'??

 

[westward10]

I'd argue the opposite, in that any good electrician will always figure out if 10mm is needed rather than just upgrading it for the sake of it. Okay, the cable may not cost much, but some bonding runs are a nightmare. From the calculations I've done over the past few years I've yet to encounter a house with a TT or TN-S supply that actually needs 10mm.

What calculations are these.
OP, have you checked for bonding yet.

 

[DPG]

Doh. Main bonding not main earthing conductor. Must read question properly. Or rtfq . Daz.

 

[Midwest]

For myself, domestic work, I find it simpler to have a drum of 10mm in the van to use for bonding services. I've even used it for earthing conductor for TT

 

[hightower]

What calculations are these.

The adiabatic to size the earthing conductor, then bonding conductors can be sized based on the result of this.

For myself, domestic work, I find it simpler to have a drum of 10mm in the van to use for bonding services. I've even used it for earthing conductor for TT

That's what we have - massive roll of 10mm, and it gets lashed in for everything. But the OP said it was procedure to have 10mm in domestic for bonding when this simply isn't true.

 

[Midwest]

Think that's the problem with being a bit aloof with ones replies, people get the wrong end of the stick and a little bit excited.

OP, you still there?

 

[westward10]

The adiabatic to size the earthing conductor, then bonding conductors can be sized based on the result of this.
I find it difficult to believe anyone would do this on a rudimentary domestic installation.



That's what we have - massive roll of 10mm, and it gets lashed in for everything. But the OP said it was procedure to have 10mm in domestic for bonding when this simply isn't true.