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My grandson is confused by conflicting information given by contractors quoting to rewire his house, which is a small 3 bed semi.
The incoming mains and meter are located at the front of the property (external meter cupboard). The consumer unit is located in the kitchen at the rear of the property.
One contractor has quoted for an 80 amp switched fuse at the meter location and running , within the property, a T&E 16 mm cable to the consumer unit. They also want to run a separate earth conductor to the T&E cable to the consumer unit. The distance from meter to consumer is some 10 metres.
The consumer unit, as well as controlling circuits within the house, will also supply a feed to a domestic garage and garden shed situated some 40 metre from the consumer unit. The electrician proposes to run a 3 core SWA cable size 2.5 mm. to a smaller consumer unit in the garage. This unit to supply Fridge Freezer. Tumble Drier. Lights and approx three 13 amp sockets.
The confusion comes because the quotes obtained are all different. I accept that are likely to be differences with regards to labour charges but expected there to be conformity with regards to cable sizes etc and similar approaches to the installation.
Can any one clear up this confusion.
 
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stevethesparks

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How would they run the Twin & Earth from the meter position?
I would suggest a 3 core SWA (steel wire armoured) cable instead.
Apart from being more suitable it will probably be cheaper too.
 

telectrix

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One contractor has quoted for an 80 amp switched fuse at the meter location and running , within the property, a T&E 16 mm cable to the consumer unit. They also want to run a separate earth conductor to the T&E cable to the consumer unit. The distance from meter to consumer is some 10 metres.

that is how i would do it, but preferably use 16mm SWA

The electrician proposes to run a 3 core SWA cable size 2.5 mm. to a smaller consumer unit in the garage.

i would run a 6.0mm SWA to allow for future increase of load, otherwise, as above.

what did the other electrician advise?
 

Pete999

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My grandson is confused by conflicting information given by contractors quoting to rewire his house, which is a small 3 bed semi.
The incoming mains and meter are located at the front of the property (external meter cupboard). The consumer unit is located in the kitchen at the rear of the property.
One contractor has quoted for an 80 amp switched fuse at the meter location and running , within the property, a T&E 16 mm cable to the consumer unit. They also want to run a separate earth conductor to the T&E cable to the consumer unit. The distance from meter to consumer is some 10 metres.
The consumer unit, as well as controlling circuits within the house, will also supply a feed to a domestic garage and garden shed situated some 40 metre from the consumer unit. The electrician proposes to run a 3 core SWA cable size 2.5 mm. to a smaller consumer unit in the garage. This unit to supply Fridge Freezer. Tumble Drier. Lights and approx three 13 amp sockets.
The confusion comes because the quotes obtained are all different. I accept that are likely to be differences with regards to labour charges but expected there to be conformity with regards to cable sizes etc and similar approaches to the installation.
Can any one clear up this confusion.
With only you description to go by it is difficult to visualize the installation, however a question, is the CU position a new one?
How has he come up with the calculations for the 16mm2 TWE and the 2.5mm2 SWA to the outbuilding, the extra Earth cable he proposes could be that the CPC in the 16mm2 cable insn't large enough to cope with any bonding requirements, where in the UK are you situated, could be someone on the Forum nearby to you could visit and advise.
 

Risteard

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I wouldn't run too much off 2.5mm^2 over 40 metres. Sounds pretty undersized for what you want.
 
T

The Ghost

For a start if it is a re-wire why not move the consumer unit to the front of the house? That saves the cost and labour of swa to the back of the house. That then would make a 50?m run to the garage/shed. Are they adjoined or is it a further run to the shed/garage? By my calcs for a 50m run (buried in ground) assuming a 32a max load I would be using 10mm² due to volt drop and I am not sure I would export (presuming TN-C-S) that far and may make it a TT (earth stake installation) That is just to the garage not taking into account the shed. I may do a separate run for that but then I do not know the lay out of things.
 

davesparks

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Since it is a complete rewire you don't nevessarily need to put the new CU in the same location. If possible I'd look at putting it within a short distance of the meter so that the submain can be avoided.
 

telectrix

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Since it is a complete rewire you don't nevessarily need to put the new CU in the same location. If possible I'd look at putting it within a short distance of the meter so that the submain can be avoided.
fair comment, but that would mean extending all the final circuits.
 

telectrix

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Why would you need to extend them?, you would obviously run the new, re-wired circuits to the newly located DB?
my bad. forgot that OP was having a rewire. don't get the cross out yet. upload_2019-3-9_13-8-50.jpeg :D:D:D.
 

Wilko

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Hi - as there isn't a specification for the Electrician to quote against they will each do their own design and quote to that. Hopefully all will be compliant with regulations, but one might have more capacity but may be more expensive. Some will involve moving the CU, others not. Even CUs vary between £100 to £300 for something that seems the same (think cars ...).
Can I ask why is the rewire being done?
 

Paignton pete

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Hi Graysonlad,

The more electricians you ask the more different ideas you will get.
A room with 5 sparkies. Give them an electrical problem. You could get five different solutions all perfectly acceptable.

Unfortunately you've just asked a forum with a lot more than five sparks.
Prepare to be overwhelmed.

Saying that what your spark has proposed seems perfectly acceptable. Obviously without a site visit and apropriate cable calcs I cannot be definate on that.

Good luck Peter.
 

littlespark

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Don't go with the cheapest quote. Just saying

Hi ho, Silver, Awaaaay
 

ChrisElectrical88

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Bored would be moving closer to the meter if possible, if not 16mm SWA, and a 6 or 10mm is going out to the garage and shed TTed.
 
  • Thread Starter Thread Starter
  • #20
My Grandson is away on holiday and I can't ask him for clarification on the excellent points raised in reply to my posting.
I think the 16 mm T&E , from meter to Consumer Unit, is following the route of the current mains cable. That is; via the cavity wall at the front and under the floorboards.
Not sure if it is a total rewire or is just updating and re positioning/installing extra sockets.
The garage installation (swa cable) is new. I think the 40 mtr I mentioned is an inclusive distance from house to garage and to garden shed. The distance from house to garage would not exceed 10 mtr. I agree that the swa, for garage and garden, should be greater than the 2.5 mm swa cable mentioned i.e. 6 mm to cater for future loads.

Thanks for the comments and apologies for the vagueness of the information. I live some 200 miles from the family and it is some years since I visited the house.
 

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