Pre-Emptive Wiring for future loft conversion

[Sard]

Hi,

I'm currently renovating my house and have my floorboards up etc and I was wondering if there was any harm in pre-emptively running a set of 2.5mm and 1mm twin & earth cables from the loft down to the Consumer Unit for lighting and power. We're looking at doing a loft conversion next year but don't want to disrupt the work in the floors below. The wires will be unattached to the CU or any appliances and run between drywall and the outside wall. My CU has slots available for two additional circuits.

I'd appreciate any advice if there are any cons to this approach?

Thanks in advance

 

[AndyPRK]

Sounds like a great idea.

I assume you won’t be needing any electric heating ?

 

[Sureitsoff?]

you should also consider any coax and/or ethernet cables if you have access to put cables in ahead of works

 

[Sard]

Sounds like a great idea.

I assume you won’t be needing any electric heating ?

Thanks

No electrical heating. We are moving our boiler and cylinder up to the loft now in preparation and will get two new radiators plumbed in when we do the conversion.

One other question about my wiring. I'm assuming it's ok for wiring to unsecured behind the drywall? I'm simply planning to feed it down from loft to CU in a vertical drop

 

[AndyPRK]

Technically they should be clipped every now and then with metal clips to prevent firemen getting injured. But if there are already loose cables a few more won’t make a difference.

 

[AndyPRK]

Consider where the boiler will get it’s power from. You may or may not want a
1mm or 1.5mm feed for that rather than tag it off the upstairs lighting.

Would be a benefit if you were to have a new fusebox.

The loft light could always be connected to downstairs lights for now

 

[Sard]

Consider where the boiler will get it’s power from. You may or may not want a
1mm or 1.5mm feed for that rather than tag it off the upstairs lighting.

Would be a benefit if you were to have a new fusebox.

The loft light could always be connected to downstairs lights for now

Thank you, that's a really good point. My understanding from the plumbers that have been quoting is that the will extend the existing wiring to power the boiler and immersion heater in the cylinder. Logically I would assume it would be sensible to have new wiring in place but would the above also be reasonable?

 

[AndyPRK]

for the immersion, it's reasonable to just extended it from the cupboard. It's on its own circuit now, which is the main thing.
They could just put a fused switch off the immersion feed to do the boiler. I wouldn't have an issue with that.

 

[333rocky333]

Cables also need to be run in safe zones, your cables behind the drywalls may be out of Zone where they pass through the other rooms

 

[Sard]

for the immersion, it's reasonable to just extended it from the cupboard. It's on its own circuit now, which is the main thing.
They could just put a fused switch off the immersion feed to do the boiler. I wouldn't have an issue with that.

Thank you, that makes sense to me.

 

[Sard]

Cables also need to be run in safe zones, your cables behind the drywalls may be out of Zone where they pass through the other rooms

For the new wiring, it's a straight run from loft into CU running between the property wall and drywall. The only room it passes through is a bedroom with no wires or plumbing along that wall.

 

[AndyPRK]

google safe zones.

It basically says that wires should be run in line with an accessory (e.g a socket or switch) or in the corner of a room.

This prevents people in future drilling thru the cable

 

[Sard]

google safe zones.

It basically says that wires should be run in line with an accessory (e.g a socket or switch) or in the corner of a room.

This prevents people in future drilling thru the cable

Understood, thank you for the guidance!

 

[winston1]

Would be a benefit if you were to have a new fusebox.

WHAT? Fuseboxes have not been installed for decades.

 

[SUNRAY]

for the immersion, it's reasonable to just extended it from the cupboard. It's on its own circuit now, which is the main thing.
They could just put a fused switch off the immersion feed to do the boiler. I wouldn't have an issue with that.

If the existing immersion switch is in a convenient place, I'd fully expect it to remain there and the 'load' side simply extended to the new cylinder position.
How often do you use the switch? Worth considering the (in)convenience of moving it.