Electric to Outside Pre-Fab Garage,

[Briansmad]

I want to connect some electric to inside garage, I have had all the work done, Plastic yellow pipe about 4 inches round under floor in house and under garage base then under block paving outside garage at least 50cm deep. Can i use noraml 16MM twin and earth cable??? From inside/house consumer unit to garage consumer unit? No one will be digging block paving up. Or digging concrete garage base up. If not Why and waht are the dangers??? Thks.

 

[Gaz the Sparky]

Isnt yellow pipe for gas

plastic wont offer any real protection against a spade realy you need SWA (Steel wired armour )

GTS

 

[ELZ4742]

yeah, agree with gaz. t&e tends to get very brittle in an enviroment that keeps changing, i.e. warm, damp freezing.

swa would be a beeter bet.

what are you planning on supplying btw?

 

[Briansmad]

Yes yello pipe is for gas, LOL, Only for lights, sockets, and will be using normal power tools and maybe a welder. Any idea what size swa i need to connect to 16mm twin and earth? Will leave connection boxes in house and take SWA to garage, Thks.

 

[ELZ4742]

16mm would be over kill IMO, as long as your not exceeding 25m a 2.5mm would suffice off a 20a breaker
but its better to over kill as you never know what your going to need in the future so a 6mm on a 32a would be better.

edit.... sorry didnt read the post properly.

i would fuse down the 16mm t&e and do the above

 

[Briansmad]

i am thinking for 16 mm cable as already in and routed under floors in house. then 10mm SWA cable to garage consumer unit. Garage has 3 trip switches 32 & 16 & 6amp. I have a spare 45 or 32 amp in house consumer unit.

 

[ELZ4742]

the problem with that is that without adequate protection your running the risk of petential hazards. you sould never use 2 different cable sizes on 1 circuit without it being fused down.

 

[Briansmad]

so it would need to be 16mm twin and earth and 16mm swa? I can buy another consumer unit small one to bring the current down, for the SWA.
So would be 16mm from main CU, to another consumer unit, then 10 mm from new consumer unit to garage consumer unit. WOW sounds a pain, i think i have some 6mm cable. might change it to 6mm and 6mm. would be easier,

 

[ELZ4742]

yeah, i understand your frustration. the chances are you will never get a problem but its not worth the risk.

depends how much hassle and cost each situation involves as to which way round you should do it.

 

[davy_owen_88]

You do not have to use the same cable throughout so long as the protective device is sized to suit the smallest cable used.

Davy

 

[ELZ4742]

but i thought that is only the case if the smallest cable was in the CU.

whats stopping someone else uprating the fuse without the knowledge that there was a change in cable size?

 

[bernardgreen]

You do not have to use the same cable throughout so long as the protective device is sized to suit the smallest cable used.

Davy

Careful Davy...... That is to much like common sense

 

[ELZ4742]

You do not have to use the same cable throughout so long as the protective device is sized to suit the smallest cable used.

Davy

Careful Davy...... That is to much like common sense

i dont think thats common sense at all.

i have a great idea, i need to wire up a new workshop so ill use 10mm off a 6a lighting circuit. im moving next week so who gives a **** that it will trip.

whats the first thing the new owner will most likely do?

 

[bernardgreen]

You do not have to use the same cable throughout so long as the protective device is sized to suit the smallest cable used.

Davy

Careful Davy...... That is to much like common sense

i dont think thats common sense at all.

i have a great idea, i need to wire up a new workshop so ill use 10mm off a 6a lighting circuit. im moving next week so who gives a **** that it will trip.

whats the first thing the new owner will most likely do?

And he may just wire an electric shower onto the ring main after changing the MCB to something bigger than 32 amp.

 

[RF Lighting]

You do not have to use the same cable throughout so long as the protective device is sized to suit the smallest cable used.

Davy

Careful Davy...... That is to much like common sense

i dont think thats common sense at all.

i have a great idea, i need to wire up a new workshop so ill use 10mm off a 6a lighting circuit. im moving next week so who gives a **** that it will trip.

whats the first thing the new owner will most likely do?

It is no different to a 16.0mm² T&E suppling a 3kW at 200m from the source. This would be on a 16A MCB because the designer has used a bigger cable to compensate for volts drop. Just because there is a 16.0mm² doesnt mean you can whack it on a 63A MCB.

A compentnet person would check the cable at the shed end as part of the testing and see that the cable is of a reduced size at the shed, and even more so if the cable changes from T&E to SWA.