consumer unit
- Thread starter amwc
- Start date
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There is unfortunatly quite a bit more than you realise to it, for example, things that you probably haven't considered:
- There are special RCD considerations with a TT system, otherwise earth faults won't cause the circuit to be disconnected
(shock and fire risk)
- A consumer unit replacement requires a full set of tests to make sure all teh circuits that are having their protective devices changed are still safe
-Work of this nature is a notifiable service
-A consumer unit replacement requires isolation upstream
etc, I'd recommend you get some quotes in
- There are special RCD considerations with a TT system, otherwise earth faults won't cause the circuit to be disconnected
(shock and fire risk)- A consumer unit replacement requires a full set of tests to make sure all teh circuits that are having their protective devices changed are still safe
-Work of this nature is a notifiable service
-A consumer unit replacement requires isolation upstream
etc, I'd recommend you get some quotes in
would you say doing the CU is deffinately a no no?
i was going to attempt it but the more i look into it the less i feel like it.
i've done wiring before but only to an existing CU to a spare mcb. its just the earthing thats throwing me.
i was going to attempt it but the more i look into it the less i feel like it.
i've done wiring before but only to an existing CU to a spare mcb. its just the earthing thats throwing me.
Unless you are competent and have the necessary test gear this is not something that should be undertaken lightly.
This is a heart lung transplant for your installation.
By changing the CU you will change the characteristics of all the circuits so they must be tested to ensure the right things happen if/when a fault occurs otherwise you could end up with
1. Fire
2. Funeral
By testing it means more than switching it on to see if it still works!
Its even more tricky as it is a TT supply. You will need to drive an earth electrode (at least 4ft long) into the ground outside and connect it to the MET by the correct sized earth cable.
You will then use your calibrated test equipment to ensure that the impedance of the earth electrode meets the requirements as laid down in wiring regulations (assuming you are working to BS7671)?
Your incoming supply will need to be protected with a 100mA RCD - (I have NEVER seen one of those in any of the sheddywickbandqhomeabuse places.)
This special RCD will need to be a time delayed type as it will be upstream of the 30mA one that you will have provided (and tested) to protect all of the socket circuits/.
There's lots and lots more.
Oh yes, and when you come to sell your house, the buyers solicitor will want to see the installation certificate and Certificate of Compliance for the electrical works. Its hard enought to sell a house at the moment and the estate agent that i do some work for has three houses that have stalled in the selling chain because electrical work has been done but no believable paperwork is around.
Go to www.competentperson.co.uk and type in your postcode. Get three quotes and choose the one who takes the least sugar in his tea...
This is a heart lung transplant for your installation.
By changing the CU you will change the characteristics of all the circuits so they must be tested to ensure the right things happen if/when a fault occurs otherwise you could end up with
1. Fire
2. Funeral
By testing it means more than switching it on to see if it still works!
Its even more tricky as it is a TT supply. You will need to drive an earth electrode (at least 4ft long) into the ground outside and connect it to the MET by the correct sized earth cable.
You will then use your calibrated test equipment to ensure that the impedance of the earth electrode meets the requirements as laid down in wiring regulations (assuming you are working to BS7671)?
Your incoming supply will need to be protected with a 100mA RCD - (I have NEVER seen one of those in any of the sheddywickbandqhomeabuse places.)
This special RCD will need to be a time delayed type as it will be upstream of the 30mA one that you will have provided (and tested) to protect all of the socket circuits/.
There's lots and lots more.
Oh yes, and when you come to sell your house, the buyers solicitor will want to see the installation certificate and Certificate of Compliance for the electrical works. Its hard enought to sell a house at the moment and the estate agent that i do some work for has three houses that have stalled in the selling chain because electrical work has been done but no believable paperwork is around.
Go to www.competentperson.co.uk and type in your postcode. Get three quotes and choose the one who takes the least sugar in his tea...
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If you have a TT installation it is always worth starting by asking your supplier if they can provide you with Protective Multiple Earthing. It is frequently available even on overhead supplies these days. it might cost you £50 to £100 but it will be money well spent. there is a slim chance they might even do it free.
You will have to provide an earth block with a 16mm G&Y cable for them to connect into the new terminal, as they like to seal it.
Start by writing to the address on your electricity bill. It will be another company that does the work, but it is not your responsibility to work out who; it is your supplier's responsibility to know and to pass the request on.
If you have a very old, damaged, or cast-iron service head, say so and ask for that to be replaced as well.
Letters are less likely to be fobbed off or ignored than phone calls.
You will have to provide an earth block with a 16mm G&Y cable for them to connect into the new terminal, as they like to seal it.
Start by writing to the address on your electricity bill. It will be another company that does the work, but it is not your responsibility to work out who; it is your supplier's responsibility to know and to pass the request on.
If you have a very old, damaged, or cast-iron service head, say so and ask for that to be replaced as well.
Letters are less likely to be fobbed off or ignored than phone calls.
As a catchall... no, with your current (pun not intended) level of knowledge, I'm afriad it is a no no
Electrics are one of those things where it is all too easy to be ignorant as to the amount that you don't know, theres a good saying "a little knowledge is a dangerous thing"
Theres probably more to the wiring that you already did than you reaslise... did you consider: Earth fault loop impedance, voltage drop, current carrying capacity with reference to installation method, de-rating factors, inspection and testing, and so on?
Unfortunatly earthing is pretty important, the problem with TT systems is that the earth is of a much higher impedance than a TN system, incidentally, have you asked your supplier if they can provide a TN earth?
i wasn't ever thinking about cutting corners i know it is notifyable but i was under the impression a third party could sign it off in the past i have paid for an inspection just to make sure.
surely there is work i could do comfortably to save a few pennies in a rewire i.e. chasing out, routing cables putting back boxes on etc?
And thanks for the advice about the PME
heres a pic of the "current" CU
http://img147.imageshack.us/my.php?image=p1010228ch1.jpg
surely there is work i could do comfortably to save a few pennies in a rewire i.e. chasing out, routing cables putting back boxes on etc?
And thanks for the advice about the PME
heres a pic of the "current" CU
http://img147.imageshack.us/my.php?image=p1010228ch1.jpg
Your original post was about a consumer unit. Now its a complete rewire!
Do we assume its the whole enchilada??
First off. Most electricians who are registered with Part P schemes are only allowed to certify their own work.
I cant and wont do it - i am taking on the whole responsibility for stuff i had no control over - its my *rse that get sued.
You've got two choices:
1. do it yourself but notify the local authority BEFORE YOU START. Pay their fee.
They will then inspect at regular intervals and should test at the end.
2. Work with a spark that will let you do some of the grunt. Personally I hate bashing houses so I'm not unhappy if the client wants to get all dusty instead of me. BUT I want to oversee what is being buried in the walls before I'll test and cert the thing.
Do we assume its the whole enchilada??
First off. Most electricians who are registered with Part P schemes are only allowed to certify their own work.
I cant and wont do it - i am taking on the whole responsibility for stuff i had no control over - its my *rse that get sued.
You've got two choices:
1. do it yourself but notify the local authority BEFORE YOU START. Pay their fee.
They will then inspect at regular intervals and should test at the end.
2. Work with a spark that will let you do some of the grunt. Personally I hate bashing houses so I'm not unhappy if the client wants to get all dusty instead of me. BUT I want to oversee what is being buried in the walls before I'll test and cert the thing.
TTC
Its because i was going to do it all myself and had a question regarding the CU
The rest of the components all seemed straight forward
if i have to get an electrician in to do the CU then i had questions about the rest of it.
Don't know why the link isn't working
Its because i was going to do it all myself and had a question regarding the CU
The rest of the components all seemed straight forward
if i have to get an electrician in to do the CU then i had questions about the rest of it.
Don't know why the link isn't working
You'll need to save a lot of pennies to make paying the notification fee justifiable!
I have to agree with the others and advise against doing this work yourself.
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