Electric cable under laminate flooring

[jordy_boy]

Hello, I did search for this but was worried information I found might be out of date.

Basically I have a large shed about 13m from back of house then it's another 4m inside the house to the cupboard with the consumer unit. I would like to get some electrics to the shed at some point in the near future for some lights and maybe 2 to 3 sockets for power tools a freezer and the tumble dryer.

Before this however I have some laminate floor to lay in the room between the CU and the back of the house. My thinking was is it good to plan now for the best route of the cable to the shed before laying the floor? The floor is concrete and I was wondering can I put a channel in the concrete for either a cable in metal conduit or reinforced cable to run directly to the shed then put the laminate on top?
Obviously I would need to work out how much cable and leave it coiled up each end for the electrician. First is this legal and second would the electrician want to see how it is under the floor anyway so be a waste of time?

Thanks for any help

 

[oldbutnotdead]

There's a lot to consider with your little scheme. Short version- find a local Part P accredited electrician, tell them what you'd like and get their opinion on what is possible and what isn't and what would be needed to achieve it. You might be pleasantly surprised at how little it will cost you to have the job done (if you take on donkey jobs like digging trenches).

Cable under laminate- doesn't sound very good. Do you know what the floor construction is- if fairly modern you might find there's a thinnish screed then insulation, which would be unfortunate. Better looking for another route. One favourite way of doing such a job is to use T & E inside the house, run behind kitchen units or up to the 1st floor then through the floor void to outside then terminate in a waterproof enclosure and continue in SWA down the house wall and underground to the shed. But that's for your electrician to decide (since they'll be signing the paperwork to say they designed and installed the system)

 

[winston1]

I don't think there is such a thing as a part P accredicated electrician. Part P is part of the building regs, no more than that.

 

[JohnW2]

I don't think there is such a thing as a part P accredicated electrician. Part P is part of the building regs, no more than that.

Given that we appear to be talking about notifiable work (a 'new circuit' from the CU), I think it's fairly clear that what was meant was an electrician who is a ('self certifying') member of a competent persons scheme.

Kind Regards, John

 

[oldbutnotdead]

Given that we appear to be talking about notifiable work (a 'new circuit' from the CU), I think it's fairly clear that what was meant was an electrician who is a ('self certifying') member of a competent persons scheme.

Kind Regards, John

Yeah that. For the reason mentioned

 

[jordy_boy]

Thanks for the advice much appreciated. I know the concrete floor is at least 2 or 3 inches thick as it has a gas pipe buried in it across the kitchen floor.
Would be a lot of trouble getting under the floor upstairs as it's all wooden flooring over the floorboards.
There is a cupboard right next to the CU cuboard which I could drill into and take the wire along the back of, then I suppose its just along one wall with central heating pipes along skirting. So wire along that won't make much difference to the look of it then it's the outside wall. As you say probably best to speak to electrician tho to see what he would want.

Thanks again.

 

[flameport]

If you must put it in the floor, then 25mm steel conduit would be a decent solution. Properly installed so that wires can be pulled in later.

 

[ban-all-sheds]

Choose your freezer carefully - many won't work properly in sheds in the winter.

 

[oldbutnotdead]

Choose your freezer carefully - many won't work properly in sheds in the winter.

Freezers are fine, as are fridges. Its fridge-freezers that play up. Reason- there is only 1 compressor and 1 thermostat on a fridge-freezer and the thermostat is in the fridge bit. Which has always seemed a bit guess and go to me but hey......

 

[JohnW2]

.... there is only 1 compressor and 1 thermostat on a fridge-freezer and the thermostat is in the fridge bit. Which has always seemed a bit guess and go to me ...

Is that not probably because it's more important to maintain the fridge at the appropriate temp (not too warm, and certainly not sub-zero) than it is to maintain the freezer at a precise temp?

Kind Regards, John

 

[ban-all-sheds]

I'm afraid you're wrong on more than one count there.

It is freezers which play up (possibly also F/Fs). And it's not because of where the thermostat is, it's because they stop working when the ambient air gets too cold.

 

[oldbutnotdead]

Thanks for the advice much appreciated. I know the concrete floor is at least 2 or 3 inches thick as it has a gas pipe buried in it across the kitchen floor.
Would be a lot of trouble getting under the floor upstairs as it's all wooden flooring over the floorboards.
There is a cupboard right next to the CU cuboard which I could drill into and take the wire along the back of, then I suppose its just along one wall with central heating pipes along skirting. So wire along that won't make much difference to the look of it then it's the outside wall. As you say probably best to speak to electrician tho to see what he would want.

Thanks again.

Depends which way the joists run upstairs- if the floorboards are across the direction the cable would go then the joists will be parallel so not a big deal (dead easy cutting out little bits of floorboard these days with these oscillating cutter tools....but simplest is best, see what your spark reckons.
PS While you're doing the job, imagine the biggest power tool you're ever likely to want in the shed then double it. For the cable lengths you're talking, labour willl be the biggest cost so well worth over speccing the job
PPS And while you're digging the trench in the garden, think about throwing a duct in for comms (alarm, data, anything else you might fancy)

 

[oldbutnotdead]

I'm afraid you're wrong on more than one count there.

It is freezers which play up (possibly also F/Fs). And it's not because of where the thermostat is, it's because they stop working when the ambient air gets too cold.

I'm assuming you mean there isn't enough of a temperature difference between 'outside' and 'inside' for the whole adiabatic thing to work properly- fair point but I had a freezer (and a fridge for that matter) in an unheated utility room for years- ambient probably didn't go much below zero but both worked fine so I didn't bother measuring temps (only energy). Annoyingly, energy consumption on both only varied by pence per month between winter and summer

 

[oldbutnotdead]

Is that not probably because it's more important to maintain the fridge at the appropriate temp (not too warm, and certainly not sub-zero) than it is to maintain the freezer at a precise temp?

Kind Regards, John

Again fair point- frozen milk is a real chore to pour on the cornflakes (sure a few others here will remember opening the front door to get the milk in that milkman had left and finding the top pushed up by a milk icicle ). As with many things, multifunction devices tend to do one job well and the other job(s) adequately. Think washer/dryers......

 

[JohnW2]

Again fair point- frozen milk is a real chore to pour on the cornflakes (sure a few others here will remember opening the front door to get the milk in that milkman had left and finding the top pushed up by a milk icicle ). As with many things, multifunction devices tend to do one job well and the other job(s) adequately. Think washer/dryers......

Indeed. I think that BAS and yourself are probably both right. There is certainly a problem in relation to the refrigeration cycle, particularly with freezers, if the ambient temp is too low. However, your point about fridge freezers is also valid. If, because of a sub-zero ambient temp, the temp in the cavity of the fridge gets close to zero (which it might, particularly if the door is opened), the machine has no choice but to switch off the compressor and, if that situation persists, the freezer will gradually warm towards ambient.

It's interesting that an increasing number of all three types of appliance (fridge, freezer and F/F) seem to be claiming that they are OK to use in unheated outhouses. That's probably a response to 'demand'. If my circle of family/friends is anything to go by, it's fairly common for people to have freezers (and sometimes one of the other two) in garages/sheds etc.

At least washer/dryers don't try to use the same type of technology (other than the drum rotation) to wash and dry

Kind Regards, John