What size RCD for mainswitch

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N

nrg

Hi

I recently visited a property who had an old style (Black with yellow button) RCD that was not functioning. It has an old re-wireable fuse board rated at 60amps for the main switch. I replaced the old RCD with a new one (customer didn't want a new CU) and tested to make sure it tripped as should an it did. My question is what size should I have installed (Ampage) when it has a 100amp 1361 Type II Service Head ?

Thanks
 
Because, as a conscientious electrician, I want to make sure that what I have done is correct. I thought this forum was here to help improve the quality of electrical installations in the UK. Sorry I must have got the wrong end of the stick !!!
 
You should use a device that is rated at or higher than the expected load.
You should have determined this value when you filled out the section in the EIC for supply characteristics.
 
Spin

Can you quantify that ? "You should use a device that is rated at or higher than the expected load."
So if I expect them to use no more than 45amps a 63amp RCD would sufficient ? What about the 100amp main fuse ? doesn't that come into it ?
 
If there is a 100A main fuse, then it would suggest that the expected load is 100A.
However the fact that the service head has 100A on it does not necessarily indicate that the fuse within is 100A, that is just an indication of the maximum amperage the head is designed for.
 
Thanks guys

No didn't confirm that the head was actually 100amp but it was only installed about a month ago as part of a refresh program in our area. The property has minimal load, has gas central heating and only a single cooker & gas hob ! I have just spoken to Elecsa and they have advised that if it is a direct replacement then 63amps is fine if there was no sign over thermal damage. (which there wasn't) I am going back to do some other work for them on Friday so might just swap to 100amp and be done with it. Thanks again
 
If the head was replaced recently, then the DNO should be able to inform you of the size of fuse installed.
One option would be to remove the fuse and have a look, though doing such is apparently frowned upon.
A bit surprised that the DNO did not offer a TN-C-S earth connection with the upgrade?
 
nrg said:
Because, as a conscientious electrician, I want to make sure that what I have done is correct. I thought this forum was here to help improve the quality of electrical installations in the UK. Sorry I must have got the wrong end of the stick !!!
Click to expand...

As a conscientious electrician you should have convinced them to change the rewirable board for an up to date version even just on economic principles,if the rcd had worn out through time it would be reasonable to assume the breakers,main switch and other control gear will be in a similar condition,for this reason I would have said Get a new board put in,its not going to cost that much extra anyway and imagine paying for a new rcd this week and then next week you need to replace the main switch.
 
Prat P said:
As a conscientious electrician you should have convinced them to change the rewirable board for an up to date version..............................
Click to expand...

Ey up, here we go again!!!

popcorn3.gif


:smilielol5:
 
nrg said:
Hi

I recently visited a property who had an old style (Black with yellow button) RCD that was not functioning. It has an old re-wireable fuse board rated at 60amps for the main switch. I replaced the old RCD with a new one (customer didn't want a new CU) and tested to make sure it tripped as should an it did. My question is what size should I have installed (Ampage) when it has a 100amp 1361 Type II Service Head ?

Thanks
Click to expand...
That is called a voltage trip, there was never an RCD there, now you have installed one what is your next move ?
 
nrg said:
Because, as a conscientious electrician, I want to make sure that what I have done is correct. I thought this forum was here to help improve the quality of electrical installations in the UK. Sorry I must have got the wrong end of the stick !!!
Click to expand...
Fair enough and I don't intend to give you a hard time, in future do an assessment of the installation first though, you removed a voltage trip and stuck a 63 amp RCD in without really thinking about it, we all make mistakes, luckily this time it won't kill anyone.
 
Tony said:
Another fully qualified rip off merchant.

If they didn’t want a new CU that is their choice, your choice is to do as you’re asked or walk away.
Click to expand...

No I am not a rip off merchant I am simply being conscientious which was the point of my reply,I dont know what your job is but mine is a bit more complex than 'just do as your asked or walk away'..do customers know what is needed for their installation to be safe? No they do not,I only gave my legitimate opinion and I qualified my opinion with facts,i.e. Age of equipment,anticipated maintenance costs,additional labour..I think my decision to advise a new board is justifiable and I resent being referred to as a rip off merchant so kindly choose your words more appropriately or back your claim up.
 
An existing 3036 board is perfectly safe if it has not suffered any damage.
For you to say that the installation needs a new CU to be safe is the scaremongering tactic of a cowboy.

If after discussing the possible advantages of replacing the CU the customer doesn't want it done then there is no problem with that.
 
davesparks said:
An existing 3036 board is perfectly safe if it has not suffered any damage.
For you to say that the installation needs a new CU to be safe is the scaremongering tactic of a cowboy.

If after discussing the possible advantages of replacing the CU the customer doesn't want it done then there is no problem with that.
Click to expand...

I would consider it good practice to keep an installation up to date and replacing parts of an old 3036 board would not be what I call good practice although your opinion is different,it does not make me a cowboy. We all employ lateral thinking in this job and it could equally be argued only a cowboy would consider continuing to maintain a board that is/or is becoming obsolete to be acceptable!! For valid reasons why see my previous comment regarding age of equipment etc...
who the hell wants to be looking for fuse wire in 2014 ? Pmsl
 
Prat P said:
I would consider it good practice to keep an installation up to date and replacing parts of an old 3036 board would not be what I call good practice although your opinion is different,it does not make me a cowboy. We all employ lateral thinking in this job and it could equally be argued only a cowboy would consider continuing to maintain a board that is/or is becoming obsolete to be acceptable!! For valid reasons why see my previous comment regarding age of equipment etc...
who the hell wants to be looking for fuse wire in 2014 ? Pmsl
Click to expand...

And if the customer doesn't want their perfectly safe 3036 board replaced? Would you just walk away and not do anything about the faulty voelcb ?

Plug in 60898 MCBs are a viable upgrade for such boards without changing the whole board
 
davesparks said:
And if the customer doesn't want their perfectly safe 3036 board replaced? Would you just walk away and not do anything about the faulty voelcb ?

Plug in 60898 MCBs are a viable upgrade for such boards without changing the whole board
Click to expand...

If after being made aware of the facts the customer didn't want to replace th board as long as I have done my job as best as I could by giving correct advice,then obviously just change the main switch or whatever needs replacing,that is not quite the same as 'doing what you are asked to do or walk away'. Keywords being GOOD PRACTICE. I am genuinely struggling to call the maintaining of a rewirable board GOOD PRACTICE , in the given scenario but horses for courses.
 
Prat P said:
I would consider it good practice to keep an installation up to date and replacing parts of an old 3036 board would not be what I call good practice although your opinion is different,it does not make me a cowboy. We all employ lateral thinking in this job and it could equally be argued only a cowboy would consider continuing to maintain a board that is/or is becoming obsolete to be acceptable!! For valid reasons why see my previous comment regarding age of equipment etc...
who the hell wants to be looking for fuse wire in 2014 ? Pmsl
Click to expand...
I have to agree with dave spark, sorry but there you are, and I still am intreagued why you removed a perfectly good double pole isolator from the system, you only had to remove the earth wire and the black and yellow thingy lol would have been wonderful for anyone in the future replacing the DB should the householder decide to spend some of their money.
 
Last edited by a moderator:
Prat P said:
If after being made aware of the facts the customer didn't want to replace th board as long as I have done my job as best as I could by giving correct advice,then obviously just change the main switch or whatever needs replacing,that is not quite the same as 'doing what you are asked to do or walk away'. Keywords being GOOD PRACTICE. I am genuinely struggling to call the maintaining of a rewirable board GOOD PRACTICE , in the given scenario but horses for courses.
Click to expand...
The fact is an RCD was fitted in place of a double pole isolator, if RCD protection is something the householder requested then a split dual RCD board not much more expensive than the work already carried out, the householder got robbed, they have to pay twice now :grin:
 
nrg said:
I thought this forum was here to help improve the quality of electrical installations in the UK
Click to expand...


well you are wrong by a country mile sunshine.

we're not here to hold the hand of those whom are not sure of what the ---- they are doing.

try your local college.
 
MDJ said:
The fact is an RCD was fitted in place of a double pole isolator, if RCD protection is something the householder requested then a split dual RCD board not much more expensive than the work already carried out, the householder got robbed, they have to pay twice now :grin:
Click to expand...
That was 1 of my points,someone then suggested using plug in mcb's but they wouldn't have offered the RCD protection that GOOD PRACTICE recommends,all this messing around replacing voltage trips with RCD could be avoided,THE BOARD WANTS AN UPGRADE. NO RCD PROTECTION. Job done.
 
Prat P said:
If after being made aware of the facts the customer didn't want to replace th board as long as I have done my job as best as I could by giving correct advice,then obviously just change the main switch or whatever needs replacing,that is not quite the same as 'doing what you are asked to do or walk away'. Keywords being GOOD PRACTICE. I am genuinely struggling to call the maintaining of a rewirable board GOOD PRACTICE , in the given scenario but horses for courses.
Click to expand...
Well, you have given them the choice, that is all you can really do. Assuming it is still TT, I would have thought an insulated Dual RCD Consumer unit would have been a worthwhile upgrade, in particular reducing the disruption of single circuit earth faults.
 
Prat P said:
That was 1 of my points,someone then suggested using plug in mcb's but they wouldn't have offered the RCD protection that GOOD PRACTICE recommends,all this messing around replacing voltage trips with RCD could be avoided,THE BOARD WANTS AN UPGRADE. NO RCD PROTECTION. Job done.
Click to expand...
Look if you spoke to the customer and they asked for an RCD upfront and were happy with that and thats all you did then fair enough.
 
biff55 said:
well you are wrong by a country mile sunshine.

we're not here to hold the hand of those whom are not sure of what the ---- they are doing.

try your local college.
Click to expand...

Do they do a course at your local college for toning down your arrogance? Its nice to be important and its important to be nice....sunshine :)
 
MDJ said:
Look if you spoke to the customer and they asked for an RCD upfront and were happy with that and thats all you did then fair enough.
Click to expand...

Read the thread from the start you will see that's what I suggested,others had the view that you just turn up do what your asked and walk away without making recommendations.
 
Prat P said:
Read the thread from the start you will see that's what I suggested,others had the view that you just turn up do what your asked and walk away without making recommendations.
Click to expand...
Nothing wrong with making suggestions, the OP has dropped one though, ripping out a perfectly good isolator and replacing it with a single rcd is wrong, nusience tripping here we come.
 
Don't understand what all the fuss is about.
None of us know what was discussed between the OP and the customer.
I suggest that people keep their comments pertinent to the OP and stop attempting to big them selves up with these smart arse know nothing comments.
 

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