10.0MM twin & earth to my outside garage.

[Gaz-DIY]

Hi,

I have already in place 10.0MM twin & earth to my outside garage. This is taken there by a conduit steel pipe. In the garage is a diall 13A 2 gang outdoor RCD socket. At the point the cable leaves the house its cut and the new cable is ready beside it to be connected by a junction box - that cable then goes back to a 45 amp rcd (removed just now) in the main fuse box.

All that will be run in the garage is a fridge freezer and lights - maybe small power tools now and then. The reason for the 10.0MM twin & earth was because i had 10 metres of it in the garage from a job someone done a while back.

I'm paused now before i make it live as I'm thinking - will the diall box be able to take this. I know it seems like overkill but the cable was free, anything else will cost but if the cable has to be changed then i can replace it all.

Any advice would be appreciated.

Thanks

 

[sparkwright]

The outdoor socket should accept the 10mm2 t+e.

You may need to drill a 25mm hole in the box, and use a 25mm stuffing gland, to make the cable entry good.

Chances are the 10mm2 wires will just go in the socket terminals.

If they don't, you can place terminal blocks on the ends, with a short length of smaller wire such as 6mm2.

 

[winston1]

As you have an RCD in the house you don’t need an RCD socket in the garage.

 

[sparkwright]

It would prudent to check that the '45 amp rcd' in the house actually offers both overcurrent and RCD protection. 45 amp rcd is a bit of a vague term.

 

[sparkwright]

The outdoor socket should accept the 10mm2 t+e.

You may need to drill a 25mm hole in the box, and use a 25mm stuffing gland, to make the cable entry good.

Chances are the 10mm2 wires will just go in the socket terminals.

If they don't, you can place terminal blocks on the ends, with a short length of smaller wire such as 6mm2.

EDIT. Were you intending to connect the metal conduit to the socket box?

What size is the metal conduit?

Is the metal conduit continuous or just a load of bits?

Is the metal conduit earthed?

Is the metal conduit watertight?

 

[Gaz-DIY]

Thank you for your reply's. I was a bit worried that the cable would be too much for the job it was doing and would cause concern - but seems ok. As for the house fuse mentioned above [45 amp rcd] i have since learned this is called a "Wylex plug in push button MCB" and has a range of [15A-45A] but on the push button it has the number 30A.

The diall box in the garage has new been wired with no issues. All i need to do now is connect the wire from the house to the wire coming in from the garage. They will be joined in a cupboard in the house. I'm now looking for a 45A connection unit for this purpose.

Also a good point about the use of 2 RCD units. Unfortunately the box in the garage has one built in. Thanks though.

* - "Were you intending to connect the metal conduit to the socket box?" = The box in the garage is hard plastic. The metal conduit pipe stops about 1 meter before the box (all inside the garage) so its held against the wall with normal clips before it enters the box.

[Metal conduit pipe]
* - It's 3 x 3 meters with metal copulas and metal elbows.
* - Its not earthed.
* - I have made it as water tight as i can from it leaving the house to it entering the garage with connectors at each join with duck tape over them and expanding foam at each end - mainly to stop spiders entering the house from the garage

Thanks again.

 

[conny]

Terminate the 10mm in the garage into a suitable termination box similar to this;

CED IP65 24A 5-Terminal Weatherproof Outdoor Adaptable Box 80 x 52 x 80mm | Junction Boxes | Screwfix.com, (this takes 2.5mm cable).

and then take a short length of 6mm from there to the Diall (box/2-way consumer unit).

 

[sparkwright]

Your Wylex MCB offers no RCD protection, unless there is an additional RCD in the house.

Unearthed metal conduit is not a good idea, even more so when the cable inside it is not RCD protected.

Metal couplers and elbows should make the conduit watertight, assuming they are the proper traditional threaded type, and not the ones that are simply held in place with a screw clamped to the pipe.

Duck tape and expanding foam - a very rough way of sealing things.

Does the conduit go underground, or is it all above ground?

Photos would be incredibly helpful to ensure you have a good quality job.

 

[Gaz-DIY]

Hi,

Thanks for the link to screw fix termination box. Will i need this if the 10mm is already going into the box (pic enclosed) happy to do what is suggested if it requires this.

Will i need additional RCD protection if i have the Wylex MCB in the house (fuse box) and also RCD built into the box in the garage. (Pic enclosed.)

I'm happy to earth the pipe as it comes into the house (pic enclosed.)

I have enclosed a pic of the conduit pipe and fittings.

Duck tape was only over the proper traditional threaded type couplers fitted to the pipe for extra watertight help.

Expanding foam is only for the end of the pipe to stop any dust or bugs using it as a tunnel from the garage to the house. (Pic enclosed)

The conduit go underground about 5" all the way into the garage then comes back up inside the garage.

Thanks again for all your advice - much appreciated.

This is the pipe i used. {Link}
This is the couplers. {Link}
This is the solid elbow. {Link}
This is the Diall 13A Outdoor RCD socket in the garage. {Link}
This is the joining box from the house to the garage I'm thinking of using {Link}

Thanks again - really appreciate this.

 

[sparkwright]

Personally I would earth the metal conduit.

Wrapping an earth clamp around the conduit (nice and tightly) and connecting a 4 or 6mm2 earth cable to it back to an earth point would solve that.

I suppose the earth wire could get connected where you intend to do the cable joint.

The cooker outlet plate you intend to use to do the joint is electrically ok, although it would be more professional to use an enclosure such as an adaptable box, or even a 47mm deep double pattress with blanking plate, and three 60 amp connector blocks.

An oval shaped 60 amp junction box would also be ideal, as everything you need is included.

 

[Gaz-DIY]

Good point about the earth clamp, defiantly doing that.

Maybe a Junction box like this [Link] ?

Conny mentions above taking a 6mm cable into the Diall box in the garage from a termination box that the 10mm could go into first. I'm not sure if this was because the thought was that the 10mm might be a bit big for the Diall connections or if it was because its not good taking a 10mm into the Diall box?
The thing is i have connected the 10mm straight into the Diall box already - should this be ok? - happy to do as suggested if that's safer or something.

Thanks again - sorry for the delay - been laying slabs for the first time (ouch)

 

[333rocky333]

Got to say Post #9 is one of the most impressive posts i have seen on this site

 

[conny]

Good point about the earth clamp, defiantly doing that.

Maybe a Junction box like this [Link] ?

Conny mentions above taking a 6mm cable into the Diall box in the garage from a termination box that the 10mm could go into first. I'm not sure if this was because the thought was that the 10mm might be a bit big for the Diall connections or if it was because its not good taking a 10mm into the Diall box?

Yes that was the reasoning behind my suggestion.

The thing is i have connected the 10mm straight into the Diall box already - should this be ok? - happy to do as suggested if that's safer or something.

Yes if you already have it terminated into the back of the socket then that is fine.

Thanks again - sorry for the delay - been laying slabs for the first time (ouch)