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Long Post Warning Lots of Questions: Thank you in advance for your patience and advice:


Hi All


In the next few weeks I'm planning to have a fair amount of electrical work done. The main project is revamping the electrics in the garage. At the moment the garage gets its power via a 2.5mm twin and earth in a MDPE pipe which is buried underground. The cable run from the main house to the garage is around 50 metres (estimated) likely less. Either way the 2.5mm cable isn't really adequate for the job in line with the regulations. The cable terminates in the garage at an old style fuse box and comes from an old style breaker box from the main house.


My plan is:

Update the fuse box in the main house with a new consumer unit. If I do this what tests would the electrician need to do and what problems could get revealed that would need fixing as it stands the electrics in the house work absolutely fine and I don't want to end up in a situation where I end up having to fully rewire the house because random faults appear because of switching the fuse box to the consumer unit. Would a better option be to pull from a meter tail and stick a separate consumer unit specifically for the garage. This seems to be the route taken when the electric shower was installed. Are there any practical considerations to take here or is it mainly an aesthetic choice.

I would like the cable running from the house to the garage to be switched to a 10mm SWA cable. Can this be done by simply fixing the old cable to the new cable and pulling it through or is it more complicated than that. Presumably the MDPE cable won't have crushed given it is designed for underground water supply.

For the garage itself the plan is to install a new consumer unit with appropriate protection and new lighting and new circuits. Should I source some of the equipment myself because in the case of the lighting it is quite specific or should I let the electrician do it all.

The biggest question, based on the information I have just supplied how much should I be looking at in terms of cost (I appreciate this is a difficult question to answer), so I have a ball park figure. For labour alone I am estimating roughly £500 is this within reason or am I nowhere near.


If I email an electrician with a list of the equipment I want and ask for two sets of prices one with supply and labour and one for just labour will I get a response or just get told to go elsewhere. The intention is to ask the electrician to supply consumer units and protective devices and I supply everything else. Conduit, Lighting, Switches and Cable.


Once again I appreciate any and all responses and if any further details are required please ask or if I'm asking something inappropriate please flag.
 
Replacing the CU in the house could reveal faults which are not currently obvious, this could be anything from an easily fixed neutral conductor trapped by a socket screw up to a terrible DIY mess requiring a full rewire of one or more circuits. Any sensible electrician will carry out some basic testing before removing the old fuse box to identify any major problems.
You are correct that not changing the CU will leave the faults undetected, it won't stop the faults being there or prevent the potential danger becoming a real danger and causing fire or electric shock.


Witb regards supplying materials I personally prefer it if a customer supplies their own light fittings if they are non-standard, ie. Not a pendant, batten holder, florescent batten etc.
Cable, conduit, switches, sockets etc etc I would normally supply unless I was being employed on a labour only basis. However if it is labour only then I'll be working on an hourly rate, not a fixed price.
 
How big is the MDPE pipe?
10mm SWA is a fair bit chunkier than 2.5 T&E.
Using the MDPE isn’t ideal, but will save a bit of work.
Your electrician will advise cable sizes calculated from the load you will be putting on it. If it’s just lighting and light power, then 10mm is overkill.

I’d say 500 is about right for labour alone. That’s 2 full days for me anyway
 
Replacing the CU in the house could reveal faults which are not currently obvious, this could be anything from an easily fixed neutral conductor trapped by a socket screw up to a terrible DIY mess requiring a full rewire of one or more circuits. Any sensible electrician will carry out some basic testing before removing the old fuse box to identify any major problems.
You are correct that not changing the CU will leave the faults undetected, it won't stop the faults being there or prevent the potential danger becoming a real danger and causing fire or electric shock.


Witb regards supplying materials I personally prefer it if a customer supplies their own light fittings if they are non-standard, ie. Not a pendant, batten holder, florescent batten etc.
Cable, conduit, switches, sockets etc etc I would normally supply unless I was being employed on a labour only basis. However if it is labour only then I'll be working on an hourly rate, not a fixed price.

The only DIY we've done is change is sockets, switches and light fittings nothing to the wiring. So in theory there shouldn't be much that can go wrong.

Any faults haven't caused a problem so far in the past few decades and dependent on the accuracy of those plug in tester things there aren't any faults on the sockets.

Thanks for your input on that, just wondering about cost savings but at the same time don't want to get snookered elsewhere.


How big is the MDPE pipe?
10mm SWA is a fair bit chunkier than 2.5 T&E.
Using the MDPE isn’t ideal, but will save a bit of work.
Your electrician will advise cable sizes calculated from the load you will be putting on it. If it’s just lighting and light power, then 10mm is overkill.

I’d say 500 is about right for labour alone. That’s 2 full days for me anyway

The MDPE is 25mm I think I'd have to measure it to be sure, based on the 10mm SWA having an overall diameter of 18mm, I'd think it would fit through. I might be running some heavy duty machines for my hobby work so would rather have overkill and not use it than have under and need it.
 
For one I would not want an electric cable in containment that is identified as water. But even if you can get it to fit you will have a devil of a job pulling that through depending on the route and length.
At 50 meters I would say it will be a nightmare.
Proper ducting is not relatively expensive.
 
The only DIY we've done is change is sockets, switches and light fittings nothing to the wiring. So in theory there shouldn't be much that can go wrong.

Any faults haven't caused a problem so far in the past few decades and dependent on the accuracy of those plug in tester things there aren't any faults on the sockets.

Thanks for your input on that, just wondering about cost savings but at the same time don't want to get snookered elsewhere.




The MDPE is 25mm I think I'd have to measure it to be sure, based on the 10mm SWA having an overall diameter of 18mm, I'd think it would fit through. I might be running some heavy duty machines for my hobby work so would rather have overkill and not use it than have under and need it.
You could and probably will have some trouble pulling that 10mm2 cable through 50mtrs of tube on the end of some 2.5mm2 T&E in my opinion.
 
Any faults haven't caused a problem so far in the past few decades and dependent on the accuracy of those plug in tester things there aren't any faults on the sockets.

Faults may not cause problems in the day to day use of the circuit, but there may be breaks in earth live or neutral or all 3 in a ring final and the sockets would continue to work fine.
The problem occurs under fault conditions will your mcb disconnect in time? Possibly not if your Max Zs is exeeded.

As for the plug in testers they are not reliable. They can show the socket has live neutral and Earth, but sometimes the earth path can have a continuity read greater that 1000 ohms and the little green light would still beep happily.
 
The only DIY we've done is change is sockets, switches and light fittings nothing to the wiring. So in theory there shouldn't be much that can go wrong.

Any faults haven't caused a problem so far in the past few decades and dependent on the accuracy of those plug in tester things there aren't any faults on the sockets.

Haven't caused a problem so far doesn't necessarily mean that it is in good working order. There are faults such as a broken or incorrectly wired ring circuit which only become dangerous when a second fault occurs.
Or for example a house I went to a couple of years ago where the customer was getting small shocks from lightswitches, the lighting circuit had an earth connection at every point but this hadn't actually been connected to the supply earth, it was floating so that when they replaced a switch and trapped a live wire with the plate screw it made very plate screw on the circuit live. This went unnoticed for quite a while as you don't often actually touch the plate screw when operating a light switch.

The recommendation is to have a domestic installation inspected and tested at least every ten years, if yours is decades old and hasn't been tested in that time then it is sensible to get it done.
 
For one I would not want an electric cable in containment that is identified as water. But even if you can get it to fit you will have a devil of a job pulling that through depending on the route and length.
At 50 meters I would say it will be a nightmare.
Proper ducting is not relatively expensive.

It's what is already in place and its buried underground, its not like any water is going to be in there.

I don't fancy tearing up the backyard for this job to change it.

The route is actually just a straight line just underground. It is less than 50mtrs overall at least 2 metres is in the garge going to the CU and probably another 5m is under floor boards to the CU in the house.

You could and probably will have some trouble pulling that 10mm2 cable through 50mtrs of tube on the end of some 2.5mm2 T&E in my opinion.

Isn't there any specialist tools that can be used or is it literally as basic as wack some tape around it and hope it sticks.

Haven't caused a problem so far doesn't necessarily mean that it is in good working order. There are faults such as a broken or incorrectly wired ring circuit which only become dangerous when a second fault occurs.
Or for example a house I went to a couple of years ago where the customer was getting small shocks from lightswitches, the lighting circuit had an earth connection at every point but this hadn't actually been connected to the supply earth, it was floating so that when they replaced a switch and trapped a live wire with the plate screw it made very plate screw on the circuit live. This went unnoticed for quite a while as you don't often actually touch the plate screw when operating a light switch.

The recommendation is to have a domestic installation inspected and tested at least every ten years, if yours is decades old and hasn't been tested in that time then it is sensible to get it done.

Good to know. Here's hoping the testing is fine.
 
Isn't there any specialist tools that can be used or is it literally as basic as wack some tape around it and hope it sticks.

There is a technique called making a pulling eye, this involves stripping back the outer sheath and removing the cores then using the armouring to make an eye which you then attach the draw rope to. Or alternatively you csn use a cable sock which is a wire mesh thing that goes over the end of the cable amd grips tight when pulled
 
There is a technique called making a pulling eye, this involves stripping back the outer sheath and removing the cores then using the armouring to make an eye which you then attach the draw rope to. Or alternatively you csn use a cable sock which is a wire mesh thing that goes over the end of the cable amd grips tight when pulled

Good to know, there are techniques then. As I said it should be a pretty straight run, hopefully fairly painless lol.
 
Good to know, there are techniques then. As I said it should be a pretty straight run, hopefully fairly painless lol.
Let us know how you get on please
 

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