"Clever" client derated the cables!

[HoverSPRX]

So I'm currently sorting a CU change and kitchen rewire while also fixings some bodges by a have a go client, came back this week to discover that he has decided to insulate the void between ground and first without mentioning it. Now this has derated all his cables by half as they are tottaly surrounded, am I being a bit OTT or am I justified?

Cooker will now have to be low wattage single oven, fortunately the hob is gas anyway, but with the ringmains would I have to put them on a 16amp or a 20 amp? I know that 32 amp MCB must be below the actual capacity of a 2.5 ringmain but by how much would I get away with 20amp? I don't have the book with me!

 

[telectrix]

quote for replacing cables with 4.0mm. . kerrching.

 

[HoverSPRX]

Lol this will be done but I don't think he has the budget at the moment, I have already warned him about the potential of overload I'm not worried about the up and down ring, just the kitchen it's a small house with central heating so ne real requirement for regular high current items except the kitchen.

 

[Spoon]

What type of insulation has he used?
Can the insulation be moved away from the cable a bit?

 

[Silly Sausage]

What type of insulation has he used?

10 cans of expanding foam

 

[Spoon]

10 cans of expanding foam

That's so that, in the future, its easier to change the cables...

 

[PEG]

It's easier to change the customer...

 

[telectrix]

insulation between floors????? whatever next, loft insulation???

 

[HoverSPRX]

Earthwool throughout, I have moved it on the cables we installed as they were accessable still in the most part, but now I'm changing the CU I am of the mind that I should derate the circuits accordingly in order to keep things as safe as possible for now. I can't lift the floor throughout and move insulation for him without quoting as it's a lot to move, it and if he refuses then I need an alternative that doesn't leave me open to blame for leaving in an unsafe condition hence why I am concidering downgrading a few MCBs...

 

[Cid]

I think you'll be fine after taking diversity into consideration. 20amp rings are perfectly adequate for a small house.