add external light and double socket to garage questions

[Kings]

hi

i want to add an external pir controlled light to my garage and also add another double socket on a different wall to save me using extension leads all the time.

the garage is new build 2.5 years old, it has power coming in from the house using its own seperate slot in the consumer unit.

i've taken some pics to show the arrangement:-

there are 2 fused switches at the door where the cable comes in to the garage. the lower isolates the power to the garage the upper is the light switch.

the cables go up in some trunking into the roof then split off, one to the central light and the other to the double socket on the garage back wall.

i've had a read of the wiki and had a search round the forum but would rather get confirmation on what i plan to do sounds ok.

for the external light can i fit a juction box on one of the roof trusses that the light supply runs along adjacent to where i want the external light, then break into the cable, wire it into the junction box and wire in another feed from the junctions box to the external pir controlled light? so it will be controlled off the pir with no switch etc.

then for the extra double socket, can i just run a spur of the existing socket up along the roof trusses like the other wiring, then down in some conduit to where i would like the new socket situated?

many thanks for your time

 

[rjm2k]

I'm not qualified.....

Is the existing circuit protected by an RCD?

Looks like the light is "looped at the switch" which means there is no permanent live going to the light itself, so breaking into the light cable at the moment is pointless.

You could break into the socket cable for the new light instead, use a DP isolator so you can isolate the new light if needs be, something like this http://www.screwfix.com/p/mk-13a-dp-switched-fused-connection-unit-with-neon-white/58085 you could probably put a smaller fuse in too for the light and preferably use the same rating of cable (eg 2.5mm) as the rest of the socket circuit.

Alternatively, you could run a new cable to the existing lightswitch/isolator instead but make sure you still add a new DP isolator for the new light.

Post a photo of the slot in the CU too.

At a guess, it's a radial circuit so look on the wiki re extending those //www.diynot.com/wiki/electrics:socket_circuits:a2_radial

 

[PrenticeBoyofDerry]

Does the existing lighting have other functional switching or is the second fused connection unit required to switch light on/off?
There would be no problem extending socket circuit as it is already protected by a fused connection unit, but the socket will require RCD protection.

 

[ban-all-sheds]

I'd strongly advise having a double pole switch to isolate the outside light (or a 3-pole one, if the PIR is the type that also has a switched live for override) in case any water leaks cause RCD tripping...

 

[Kings]

many thanks for all the replies everybody.

i've taken some more pics of the arrangement showing some of the wiring and the consumer unit.







the lighting is switched on and off via the upper switch in the original pictures, the lower isolates everything.

i will definitely use a switch then as advised, was just trying to keep it simple for my own benefit :-/ looking at the pics does it narrow it down as to which method's best to use?

bit confused with the 2nd socket, can i just run a spur off it as the consumer unit has an rcd in it? or do i need to add a socket with the rcd built in?

thanks again for your time.

 

[Kings]

any other pointers guys?

 

[securespark]

The garage circuit is protected by a 16A MCB, on the RCD side of the board.

You can just fit a normal socket in the garage, piggy-backing off the existing. Or, if the incoming switch is closer to where you want the new socket, you can come off the outgoing terminals of the lower switch.

In fact, that lower switch (that isolates the garage supply) looks like it is fused down to 13A. It does not need to be.

 

[Kings]

great many thanks for the help

socket location wise it will be easier to connect to the existing double socket, so i can run a spur off that then?

any opinion on the best method to connect the external light?

 

[PrenticeBoyofDerry]

great many thanks for the help

socket location wise it will be easier to connect to the existing double socket, so i can run a spur off that then?

As it's a radial circuit you can spur or extend the circuit.

any opinion on the best method to connect the external light?

You will require a FCU unit, down fuse to 3A, this can be supplied from the socket radial, if you use a switched fused connection, the switch on the FCU could also be used as the functional switch for the light, if located in suitable position.

 

[rjm2k]

Is the black wire in the top pic the earth going through to the CU?

 

[Aragorn84]

Does it not look like the lighting is unfused at the moment?

Or at least, only fused by the main "isolating" fcu?

Surely thats not right?

 

[rjm2k]

There's only 1 light and 1 socket, may even be safer that way, if the light blows the shared fuse, your circular saw/drill/angle grinder/other dangerous tool stops working!

 

[Kings]

many thanks for the replies

the light switch is fused, the flash on my camera phone has blanked it out for some reason.

i will spur off the socket and use a fcu as advised then.

 

[dhutch]

Im not a spark, and have not seen the images (blocked at work) but the socket, as said, can be simply extended of the end of radial, or spured off it at an point. Is there currently only one socket?

Im slightly supprised that the lower FCU isolated both the power and the light, I dont know what the thoughts are, but I would have thought you could take the feed to the light FCU from the load side to the supply side, hence both would be fed separatly and as said, you would have more redundancy on your light going off, if still both on the 16amp trip. It would also give you smidge more power.

The outdoor light could then either be taken of the ring main (or incoming 16amp feed?) with a fused DP isolator, or taken of the load side lighting FCU with an unfused isolator and a second unfused switch added for the light?


Daniel

 

[Spark123]

Can we have a pic of the wiring in the bottom isolator from the other side please - I can't see where the grey (with blue tape/sleeve) goes to?