Driveway Light

[m4tty]

Hi,

Customer has asked for a price to install mini lamp post light at top of driveway. The CU is under the stairs in the middle of the house and would be a nightmare getting cable from here to outside as laminate floor etc.

Any suggestions where else power could be taken from?

I know it needs armoured cable which will be buried but if I could get power from ring? fused down? I know it would be better on its own circuit as adding outside stuff onto ring mains is asking for problems.

Any suggestions?

Thanks for all your help and not taking a pop at me as i am asking some basic questions but im a worrier and want to make sure ive done it all proper and correct.

Matt

 

[Andy™]

nothing wrong with taking a supply from ring main. either use a metalclad SFCU, or adaptable box where cable goes outside & changes to SWA

 

[revjames]

If it was me I would go from CU in T&E to switch, then at a suitable point fit an adaptable box and go to SWA in suitable depth trench to the lampost.

HTH

 

[Evans Electric]

Just come off the nearest socket M4tty, via an RCD spur . If there is a problem with the lampost it can be isolated.

Deke

 

[spinlondon]

Could come off a lighting circuit perhaps.

 

[moose man]

If you come off with a rcd spur unit remember discrimination with the rcd on the cu if it as one on the circuit you spur off

 

[Megaohm7]

Does the property have a garage with power ? It might be easier running your swa from there depending the set up of course . Just an idea as taking a supply from the cu could be difficult depending on the location but has been suggested before an fcu and rcd protection from the ring main is a safe option and means the lamp can be isolated too for maintenance.

 

[m4tty]

If you come off with a rcd spur unit remember discrimination with the rcd on the cu if it as one on the circuit you spur off

Hi mate,

How can you achieve discrimination if the CU is split load (both sides covered by 30 mA RCD) and you want to install a RCD Spur unit as they are 30mA too?

Cheers

 

[ianmacd]

Hi mate,How can you achieve discrimination if the CU is split load (both sides covered by 30 mA RCD) and you want to install a RCD Spur unit as they are 30mA too?

Cheers

The only real way to provide descrimination with RCD's is for the upstream one to be time delayed. If the circuit is already protected by a 30mA RCD then I would not worry about another one.

Also (not wanting to start ANOTHER exported earth thread) be careful what you do with your exported CPC.

 

[Megaohm7]

FCU spur off ring main then adaptable box for the SWA up to the light fitting itself I would think is the safe option if the ring has already got an RCD protecting it . If a fault does develop in the light fitting and does trip the RCD on the CU then at least you have the option of switching off the FCU and resetting the RCD so power can be resumed on the ring until the fault is cleared on the light fitting . How far would the fitting itself be from the house and what earthing arrangement is there . I'm thinking outside equipotential zone ( I feel an exported cpc thread coming on ) :Blushing

 

[ianmacd]

...and what earthing arrangement is there . I'm thinking outside equipotential zone ( I feel an exported cpc thread coming on ) :Blushing

Just remember I said above I didn't want to start one of those again .

 

[Megaohm7]

Just remember I said above I didn't want to start one of those again .

Gotcha !!! :^O