garden lights - exam question

[jas_singh]

i have new mcb on consumer unit, lights switch, and 4 garden brick lights

how would you install the lights.

Include how you would wire up the wires from consumer to the switch to the lights

Include Cable to be used. its a brick wall so 2 lights on either side on the wall.

Question worth 6 marks

I know it would be SWA 1.5mm

Can anyone help with this question.

 

[Apache]

What do you think?

Have a go and we will help.

How long is the cable run?

 

[jas_singh]

well its defo going to be 1.5 SWA cable

live neutral and earth striaght to first light from consumer unit then get the live and switch wire from exterior light to one way switch. from the first light use live and neutral to power second, third and forth light

and i right

little confused

 

[binky]

Own circuit, (or take a feed off existing ciruit) switch feed to save hassle, RCD (or RCBO ) protect as special installation. Armoured cable (could be syflex) for protection against garden implements and rodents. Terminate armoured to adaptable box close to light fitting (if burying use gel compound to seal against moisture ingress. From box use syflex or similar to run into bricklights cos you can't get SWA glands in these. Make sure cable entry is sealed up, but don't forget drainage hole. Alternatively run in conduit using normal cable and suitable calculation for length of cable, running in conduit etc. May wish to consider 2 pole isolator especially if running from existing circuit to isolate garden lights should fault develope that trrips circuit.

 

[meady]

As you want all lights operated by one switch I would have the power going to the switch then from there have the switch wire linked to all lights.

 

[M107]

Seems you got the answers, but just to add my bit....

On raised brick beds I've used in the past swa glanded to 3 way besa boxes. used the besa boxes as the junction/loop point with a short length of pvc coated steel copex to the brick light (the entry hole to the brick light needs enlarging to accept the copex gland).

Fill the besa boxes with R39 compound & use rubber lid gasket if below ground level.

Last ones I did I used whiska boxes instead of conduit besa boxes.

 

[jas_singh]

meady - do you mean.............

power (live) from consumer unit (MCB) to one way switch then from one way switch wire to lights followed by neutral and earth. Then use switch + neutral(which is live) to other lights

would i get no marks if i said singles to one way switch then from one way to switch use SWA 1.5mm.

Thanks for your help.

 

[Apache]

meady - do you mean.............power (live) from consumer unit (MCB) to one way switch then from one way switch wire to lights followed by neutral and earth. Then use switch + neutral(which is live) to other lights

I think what he means is take all the wires (L,N & E) to the switch and link the neutrals and earth cables but split the live/phase/line [whatever we are calling it today] through the switch. As in 'loop at the switch' method of wiring.

would i get no marks if i said singles to one way switch then from one way to switch use SWA 1.5mm.

You can use anything you like depending where the switch is and how you will get the cable there. You could use twin and earth or singles, but the singles need additional protection as they only have one layer of insulation so would need to be in conduit, whereas T&E could be surface run if required.

Is the fictitious board RCD protected?

 

[jas_singh]

he didnt mention the board being RCD in the question

he just wanted to know how you wire 4 lights to 1 switch from a consumer unit (MCB)

 

[meady]

meady - do you mean.............power (live) from consumer unit (MCB) to one way switch then from one way switch wire to lights followed by neutral and earth. Then use switch + neutral(which is live) to other lights

would i get no marks if i said singles to one way switch then from one way to switch use SWA 1.5mm.

Thanks for your help.

As pach said mate. Twin and earth feed from cu to switch. Terminate the live conductor in the common terminal, the live conductor of switch wire in the l1 terminal then link the neutrals together and cpc together. Mention in the answer about you must provide rcd protection and also if the switch is located outside it must have a suitable ip rating. You might get extra marks

 

[spinlondon]

Why the RCD?

 

[septiclecky]

i have new mcb on consumer unit, lights switch, and 4 garden brick lightshow would you install the lights.

Include how you would wire up the wires from consumer to the switch to the lights

Include Cable to be used. its a brick wall so 2 lights on either side on the wall.

Question worth 6 marks

I know it would be SWA 1.5mm

Can anyone help with this question.

You can call me cynical but I have to agree with Apache, you should have a try to answer yourself and then post what you think is right installation asking if it is right as you won't have the benefit of asking anyone on here during the real exam to give you the answers.