unusual fault

[ev88]

hello all

unusual fault that is perplexing me.

History

garage is fed via a spur off the ring main downstairs and during heavy load, the fuse would blow.

to get around it I would turn off things on that ring main and all was fine.

later, I had fuse board replaced with circuit brekaer trips and rcd.

now the whole board trips out when I use a 2.2kw grinder on it.

to get around the issue, a line from a spare circuit breaker in the board was wired from fuse board directly to garage just like an electric cooker cable individual line. 16A rated.

but problem still persists.

Grinder can be used on the cooker socket and cause no concern so grinder is OK

3kw kettle can be used on old ring main to garage, new line to garage and any ring main in the house without issue so induction motor initial draw is causing concerns.

now the complicated bit and I shall do my best to accurately describe.

live to the board is fed via main isolation load trip switch which first enters another mains isolation before making one side of the buz bar live in the board.

this side of the board feeds a socket ring main breaker 32A rated and two lighting circuit breakers 6A rated.

the second side of the buz bar is made live after first passing through an RCD before making a cooker 32A breaker live, a socket ring main 32A and a 16A spur to garage live.

whent he grinder is used on the socket ring main of the 1st live section of the buzbar, the rcd trips out but the grinder operates fine which is confusing. when the grinder is used on the old garage socket or the new spare to the garage, the main isolation to the board trips out.

I have in mind that the rcd should maybe be replaced just to see if it is on the sensitive side but I'm a little lost why the rcd tripping out and not the breaker to the circuit it is connected. so an inbalance is causiing some fault.

the lad I use for the elecrtrics is on holiday so I would like to do a little problem solving of my own to inform of fault when he returns. also if its a simple fix then I may just fix it myself so I can do a bit of work in the garage.

this is a long winded post so many thanks to those who take the time to read and reply.

best regards

 

[EFLImpudence]

Any chance of a picture of the board?

 

[xr4x4]

Your wording is slightly confusing.

You mention 'tripping out' and the rcd tripping, is it one or the other or both?

How old is the board, single or duel rcd?

 

[sparkticus]

now the whole board trips out when I use a 2.2kw grinder on it.

What exactly trips out?

Is it an RCD or an MCB?

so induction motor initial draw is causing concerns.

A grinder usually does not contain an induction motor but does offer significant inrush on start up.

live to the board is fed via main isolation load trip switch

I do not understand. Is this an RCD?

this side of the board feeds a socket ring main breaker 32A rated and two lighting circuit breakers 6A rated.

Is it this side that "trips out" when the grinder is used.

the second side of the buz bar is made live after first passing through an RCD before making a cooker 32A breaker live, a socket ring main 32A and a 16A spur to garage live.

whent he grinder is used on the socket ring main of the 1st live section of the buzbar, the rcd trips out but the grinder operates fine which is confusing. when the grinder is used on the old garage socket or the new spare to the garage, the main isolation to the board trips out.

So the RCD that trips on the second side of the consumer unit does not disconnect the supply to the grinder (despite the grinder causing RCD to trip)? Is that right?


I know you are not an electrician but the terminology you are using is difficult to follow. As has been suggested please could you post a picture of your consumer unit.

 

[ericmark]

Trying to work out what is tripping from your report I am finding hard but I think it is the RCD that is tripping?

One problem with a TN-C-S supply is the neutral and earth are at the same polarity so a neutral earth fault can cause some at first look some odd effects.

As the current draw increases so does the volt drop until it reaches a point where enough current can flow through the neutral to earth fault to cause the RCD to trip.

Since many items only have single pole switching it may be something switched off which is causing the problem.

So with main isolator turned off so neutral and earth should be separated you need to test for neutral to earth faults.

 

[ev88]

hello all

unusual fault that is perplexing me.

History

garage is fed via a spur off the ring main downstairs and during heavy load, the fuse would blow. (on that circuit of the board only)

to get around it I would turn off things on that ring main and all was fine.

later, I had fuse board replaced with circuit breaker trips and rcd.

now the whole board trips out when I use a 2.2kw grinder on it (from the old garage socket ring main or the new line to the garage from the board) the whole board trip includes the RCD protecting one socket ring main, one cooker ring main and the newly wired line to garage + the main isolation to the whole board)

to get around the issue, a line from a spare circuit breaker in the board was wired from fuse board directly to garage just like an electric cooker cable individual line. 16A rated.

but problem still persists.

Grinder can be used on the cooker socket and cause no concern at all with no trips to speak of so grinder is OK

3kw kettle can be used on old ring main to garage, new line to garage and any ring main in the house without issue so induction motor initial draw is causing concerns (as obviously a 3kw kettle will draw more load current

now the complicated bit and I shall do my best to accurately describe.

live to the board is fed via main isolation load trip (big black switch in diagram) switch which first enters another mains isolation (the white switch on far right of board with red toggle) before making one side of the buzz bar live in the board. (right side)

this side of the board feeds a socket ring main breaker 32A rated and two lighting circuit breakers 6A rated.

the second side of the buzz bar is made live after first passing through an RCD (the larger of the breakers 4th in from left to right) before making a cooker 32A breaker live, a socket ring main 32A and a 16A spur to garage live.

when the grinder is used on the socket ring main of the 1st live section of the buzzbar (the 3rd breaker from the right after the isolation), the rcd trips out but the grinder operates fine and does not trip that breaker of that circuit which is confusing. when the grinder is used on the old garage socket or the new spare to the garage, the main isolation to the board trips out along with the RCD.

I have in mind that the rcd should maybe be replaced just to see if it is on the sensitive side (my thinking is that when I use it on the first socket ring main that allows it to work but trips out the left side of the board via the RCD perhaps that the return neutral inbalance is causing it to trip out) but I'm a little lost why the rcd tripping out and not the breaker to the circuit it is connected. so an in balance is causing some fault.

the lad I use for the electrics is on holiday so I would like to do a little problem solving of my own to inform of fault when he returns. also if its a simple fix then I may just fix it myself so I can do a bit of work in the garage.

this is a long winded post so many thanks to those who take the time to read and reply.

best regards
(I have tried to add some red comments here to inform further plus a picture and a doggy wiring layout)

 

[RF Lighting]

For the love of god get that installation isolated immediately and then refit the busbar shroud and cover to that borad and DO NOT remove it ever again whilst the installation is still live.

You got a death wish or something?

 

[securespark]

Are those blacks in the RH MCB's??

And reds in the earth terminal of the VO ELCB??

And where is the earth conductor from the electrode?

 

[sparkticus]

Can you take some pictures at different angles especially from over the top of the MCBs ?

I have never seen anything quite like this!! I'm hoping the blacks in the MCBs is just an optical illusion!!

 

[ev88]

yes they are blacks to the right hand mcb's except the 3rd breaker from the right feeding sockets.

and the earth lead from the mains isolator has 2 red wires as the earth.

I'm not best happy with the installation myself!

everything runs fine in the house except my large grinder and I did not check the installation wiring of the board after completion.

it is only now that I desire to use the big grinder in my garage that I have looked at the wiring and are confused by it.

I don't understand why only 3 mcbs arer protected by the RCD and not the lot unless there was some issue and secondly, the colour code wiring to the board leaves a lot to be desired.

I have steps in motion for an electrician where I work to come redo the work and do some fault finding.

I have simply registered with the forum tonight to get some comments.

 

[martinxxxxxx]

yes they are blacks to the right hand mcb's .....

I have simply registered with the forum tonight to get some comments.

I am sure you will get some

 

[sparkticus]

I have simply registered with the forum tonight to get some comments.

That is absolutely fine, not a problem. The problem is that this looks like a potentially dangerous mess and frankly it would be almost impossible to debug your problem via this forum given the picture. Though you apparently do not have a main earth which is a big problem. Was the consumer unit installed recently? I would suggest the grinder issue is the least of the problems.


EDIT: Aha I see the two red wires are the main earth... this thing needs urgent attention.

 

[xr4x4]

That picture is truly shocking, no pun intend.

Where do you start.

 

[sparkticus]

I don't understand why only 3 mcbs arer protected by the RCD and not the lot

In this particular case it would be something to do with the state of mind of the individual that wired it. It will probably not be anything logical.

 

[JohnW2]

I wish the picture was a little clearer - I hope I'm wrong in thinking that there might be some red wires going into the earth bar?

Do electricians have to be tested for colour-blindness?

Kind Regards, John.