Outdoor kitchen earthing

[sweet212]

Evening all,

My client is installing an outdoor kitchen in their garden. This will consist of a bespoke steel frame which will house the cooking equipment. The frame itself will be sat on a concrete floor. There will be a stainless steel gas burner (mains gas - copper pipework) and sink installed. As far as electrical loading goes, there will be 1 double socket, igniter for gas burner and some led lighting. I will be running a 16A, RCD protected radial out to it in SWA. The electrical supply is TNC-S so I am planning on disconnecting the earth at the kitchen end an installing an earth rod. I will install an MET connected to the rod. From here I will run separate bonding for for the gas pipe and steel frame work. I will earth the circuit accessories to the MET.

Have I missed anything?

Thanks for your input,

James

 

[telectrix]

make sure you earth the SWA armour at the house end, but disassociate it from your TT at the load end.

 

[sweet212]

Yes the SWA will be earthed from the metal CU and glanded into an insulated enclosure at the kitchen end. It will be at this point the circuit will pick up its earth from the rod.

Thanks

 

[Rpa07]

Sounds like a nice install. Pop a photo of it all done. All best with it. We may take a sweep stake on your Ra so if you want in take the first guess.

 

[sweet212]

Ok. The install is taking place on an existing patio. I estimate it is sat on 300mm of hardcore/rubble. Given the dry conditions we have had lately I think somewhere in the region of 60 ohms.

I will be using a 5/8" rod.

James

 

[Specialist]

I'll play: 50 ohms. Good luck with your install.

 

[westward10]

Sounds like a nice install. Pop a photo of it all done. All best with it. We may take a sweep stake on your Ra so if you want in take the first guess.

Picture of a socket and rod can't be that interesting

 

[Rpa07]

Outdoor kitchen you dufus! Got to be a little interesting - even to cynical old @westward10

 

[telectrix]

i have an outdoor kitchen. it's called a barbeque.

 

[Dave OCD]

102.6 ohms.

 

[Rpa07]

27.8 ohms - always the optimist (praying for a rainy week before rod install!)

 

[Rpa07]

@Wilko will be along in a minute with the 'exact' prediction!

 

[telectrix]

use a 12 ft. scaffold pole, . guaranteed sub 5 ohms Ra.

 

[Rpa07]

You being over critical Ian

use a 12 ft. scaffold pole(with a hose pipe and running water), guaranteed sub 5 ohms Ra.

Amended with licence!

 

[Octopus]

with only 1 x 5/8" rod ................. 187 ohms

 

[Leyland30]

159 ohms

 

[Midwest]

Just to be annoying, why not extend the TNC-S, and install an earth rod as well? It's only what the 18th is gonna make us do.

Bonding; is the metal gas pipe reappearing from the ground at the outdoor kitchen? If not, its presumably already bonded in the house. Is the metal structure going to be extraneous? Why not run a 10mm swa anyhow? Why is the swa being rcd protected?

 

[telectrix]

with only 1 x 5/8" rod ................. 187 ohms

gerroff. i have achieved 30 ohms with a 3 ft. twig. once i had connected 6 of these the reading came down to 6 ohms.

 

[Wilko]

@Wilko will be along in a minute with the 'exact' prediction!

Hah ha ha ... I love the little tables of predicted values for Ra vs rod etc. Usually the soil resistivity is a complete guesstimate and so are the results

Perhaps a thing to look out for is simultaneous contact between the two earthing systems. Check that a person can't be in contact with a conductive part from the house (say the garden tap) and the new locally bonded stuff.

Edit : agree with @Midwest #17 ... why not extend the TNCS?

 

[davesparks]

Ok. The install is taking place on an existing patio. I estimate it is sat on 300mm of hardcore/rubble. Given the dry conditions we have had lately I think somewhere in the region of 60 ohms.

I will be using a 5/8" rod.

James

And how deep will you be going with the rod?