Untraceable/unknown circuits

[ajl_02]

Upon testing an installation after a fuse board change there are 2 x circuits which ate untraceable. I have left them connected but was just wondering if these circuits would be noted down in the departures from bs7671 box on the install cert??

 

[MDJ]

after a fuse board change

Gasp!!!!!!!!

 

[ajl_02]

That helps!!!

 

[bigbaddave]

Upon testing an installation after a fuse board change there are 2 x circuits which ate untraceable. I have left them connected but was just wondering if these circuits would be noted down in the departures from bs7671 box on the install cert??

So really they could end under floorboards in a kids bedroom? and you have reconnected them.. Really..

Ive had this before on water heaters where the plumber has just left live cables under flooring and old showers too..

 

[Brightspark2]

You should of tested it before changing consumer unit...

Thats not what the departures box is for, these are departures from regulations but still offering the same level of safety.

Also if you couldn't trace them why connect them back up, leave them disconnected...

 

[kingeri]

How are they 'untraceable'?? If they are left disconnected does anything no longer work? If not, then why reconnect them???

 

[ajl_02]

Fair point but why would unknown/untraceable circuits only be a c3 on a PIR test???

 

[kingeri]

Fair point but why would unknown/untraceable circuits only be a c3 on a PIR test???

If you can't 'trace' them then you shouldn't be doing an EICR.. or changing a CU for that matter. It's not a codeable thing. If you don't know where a circuit goes or what it is for, how is this a C3? How does it not comply with the current regs??

 

[bigbaddave]

It depends on the install, a untraced circuit that you cant see any danger then a code 3. If an untraced circuit has very low IR then a 2.

But thats beside the point. Your not conducting an EICR you changing a board. how can you reconnect it if you cant confirm your dead tests? or as above why make more work if it doesn't feed anything then leave it disconnected

 

[kingeri]

C3 - I don't know where the circuit goes?????

 

[bigbaddave]

Depends on the job. If its a cheap EICR where I am testing the absolute minimum and didnt have time to trace the circuit I would code it a 3 for not being able to confirm continuity of cpc to the end.

Personally id prefer to trace it, but I certainly wouldnt be putting them back into the board on a CU change if there were not feeding anything.. Why make more work

 

[kingeri]

If anything it could be flagged as requiring further investigation. But if they genuinely don't serve a purpose, just leave them disconnected and get on with your life!

 

[ajl_02]

That sounds like the best option. Thanks

 

[bigbaddave]

If anything it could be flagged as requiring further investigation. But if they genuinely don't serve a purpose, just leave them disconnected and get on with your life!

Couldn't agree more

 

[Paul.M]

C3 - I don't know where the circuit goes?????

Your wrong mate, its a code 5. The circuit does not exist so the code for it cant lol.

 

[Brightspark2]

Fair point but why would unknown/untraceable circuits only be a c3 on a PIR test???

Used to be recommended as a code 3 on PIRs as required further investigation...but thats a different situation from yours...

But PIRs are redundant now, there EICRs with different codes...but I assume you know this...

 

[FAA Greenie]

I did a kitchen rewire last year and found an FCU feeding a 1.5mm T&E into a wall which disappeared to nowhere!! After I disconnected it I tried allsorts; outside lights, looked for spurs, under cupboard lights, extractor. All still worked.

Owner said it had just always been switched on and they never turned it off.

I left it disconnected and told the owner if they noticed anything not working I would go and test/reconnect it. I've still not heard anything to this day.

 

[Spoon]

I thought that all circuits on a CU have to be marked for the purpose they serve. e.g. Kitchen.. How can you quote to replace a CU and add the circuits back in without knowing what they do? What did you put on the new CU? What was on the original CU? What fuse rating was the original circuits wired to?
You can understand how the general public get the wrong image about electricians when they get someone to do a job and they expect the job to be done only to be told that they have to spend more money cause the job was not done fully in the first place..

 

[ajl_02]

The old board was a 3036 board with no labels at all. I've replaced it with a dual rcd board. Traced all circuits and labelled new board but there's 2 circuits which I couldn't trace. I've just been and disconnected the 2 circuits and have now just left them as spare ways in the board. I left them in because the electrics haven't been touched since the house was built until I changed the board. All sorted now.

 

[yellowvanman]

Best way is to not connect, but leave them accessible so they could be if the customer realises something doesn't work.

 

[Octopus]

If you can't 'trace' them then you shouldn't be doing an EICR.. or changing a CU for that matter. It's not a codeable thing. If you don't know where a circuit goes or what it is for, how is this a C3? How does it not comply with the current regs??

What rubbish, I couldn't disagree with you more - C3 requires investigation.

There are tens of thousands of houses around with untracable circuits in them. On an EICR its a C3, on a board change you can either leave the cable "safely" within the board or connect it to e MCB with the same rating as the old board and the MCB switched off.

Did one myself about 6 months back, EIC stated unknown as circuit description and as the owner was a retired engineer we discussed the options - we agreed to connect the cable to the MCB and leave it switched off. 2 months later got an email saying he had found what the circuit did and I duely went round and tested said circuit.

Maybe I've got the wrong end of the stick, BUT a RCD board with 1 unknown circuit in it is far, far safer than a BS3036 board with no RCD's

 

[ajl_02]

Exactly!!! The old board with no rcd protection had been used with no problem for about 30 years. The board now has rcd protection on all circuits so its gota be a lot safer than it was!!

 

[plugsandsparks]

What rubbish, I couldn't disagree with you more - C3 requires investigation.

There are tens of thousands of houses around with untracable circuits in them. On an EICR its a C3, on a board change you can either leave the cable "safely" within the board or connect it to e MCB with the same rating as the old board and the MCB switched off.

Did one myself about 6 months back, EIC stated unknown as circuit description and as the owner was a retired engineer we discussed the options - we agreed to connect the cable to the MCB and leave it switched off. 2 months later got an email saying he had found what the circuit did and I duely went round and tested said circuit.

Maybe I've got the wrong end of the stick, BUT a RCD board with 1 unknown circuit in it is far, far safer than a BS3036 board with no RCD's

Agree, when you are doing Comm and industrial i have had many issues tracing ccts, even with the help of the site based electricians, they dont know either. Its the nature of the beast.
As for the OP, nearly all old houses had an immersion heater cct but often these are redundant with combis, that may be one of them ....

 

[infinity]

^^^ Agree with Murdoch, in older installs especially comm industrial you will usually always have at least one circuit you spend over 30mins looking for until you have to move on. I'd be very surprised if you have been carrying out EICR's and always found every single circuit on older installs?

C3 - further investigation

 

[Steve_P]

These aren't a cooker and heating circuit with a 100mA time delay RCD main switch are they?

 

[kingeri]

All I meant was not knowing what a cable does isn't in itself a C3. What reg no. would you quote?

 

[High Tower]

Murdoch, thank you!!!,

Gentlemen it's not a ideal world, never will be!, there will always be unknown circuits!

I do the same as Murdoch says, I change the board and put cables in place but do not connect.

And I second that a rcd and a mcb will always be a drastic improvement on 3036's.

 

[HandySparks]

All I meant was not knowing what a cable does isn't in itself a C3. What reg no. would you quote?

At the least, 514.1.1 and 514.1.2 regarding labelling of switchgear and wiring will apply. 514.1.2 says: "So far as is reasonably practicable, wiring shall be so arranged or marked that it can be identified for inspection, testing, repair or alteration of the installation."

If you can't work out what it does, it's clearly missing labels, diagrams or schedules.

 

[Jerry H]

Upon testing an installation after a fuse board change there are 2 x circuits which ate untraceable. I have left them connected but was just wondering if these circuits would be noted down in the departures from bs7671 box on the install cert??

Have just finished a CU change on a 1960's house. There were several 'unidentifiable' circuits but we made an effort to trace them. One was an old electric clock point plastered into the wall by the fire place, another was an old electric bathroom heater and a third was some sort of weird gizmo in the loft that was supposed to stop the water pipes firing up. If you can't find them, don't connect them. They'll soon let you know when things don't work

 

[richy3333]

If you can't 'trace' them then you shouldn't be doing an EICR.. or changing a CU for that matter. It's not a codeable thing. If you don't know where a circuit goes or what it is for, how is this a C3? How does it not comply with the current regs??

Labelling?

 

[marcusone]

If I can't trace a circuit within a reasonable time I explain to client that I can continue hunting it down at x pounds per hour or leave it disconnected until they find something not working. They always opt for disconnection as the cheaper practical option. Best endeavours gentlemen.

 

[baldelectrician]

Had one today

Found 2 circuits out of 11 redundant, spent a good 45 mins checking all stuff was working (inc client moving wardrobes to get into little used sockets etc).

In the end all circuits worked and tested OK, the 2 redundant ones were disconnected and terminated inside the consumer unit incase something turned up.

In the end the client was happy- the CU was changed 8 years ago and these 2 circuits were reconnected without testing

 

[oldtimer]

Had one today

Found 2 circuits out of 11 redundant, spent a good 45 mins checking all stuff was working (inc client moving wardrobes to get into little used sockets etc).

In the end all circuits worked and tested OK, the 2 redundant ones were disconnected and terminated inside the consumer unit incase something turned up.

In the end the client was happy- the CU was changed 8 years ago and these 2 circuits were reconnected without testing

Had the exact same and did the exact same terminated cables into connector strip labelled them job done even highlighted it on the EIC plus I could sleep at night know I did no harm and if the customer phones me in 3 months time and say I knocked those built in wardrobes down and found a twin socket behind them then its a 5 minute job to connect it up but I would not like the H&S people knocking on my door to say my customer died knocking his built in wardrobes down as he touched a cable that he found coiled up behind them.

I have said this before on this forum so I will repeat myself again and will take the flack I find this type of post as a no brainer but the fact the OP has left them connected makes me wonder what type of people we are producing so the lesson is here if you cannot confirm then leave it disconnected I wont mention common sense because there does not appear to be any kicking around on this forum

 

[amlu]

had 2 6mm cables on last CU upgrade. one for cooker, yeah no problem, another one showing 30ohms insulation resistance.
after couple hours of bashing floors found it feeding a socket on another side of property, then 1.5 cable spurred of it into a junction box, for boiler and fridge supply. sic!

 

[PEG]

Surely an unidentified circuit reconnected to a new CU is crying out for one of those new stickers the CU manufacturers send out with every new CU? You know,the one with the big question-mark on it :tt1:

 

[moose]

LMAO and you have to follow the manufacturers by the BGB so one for the ? and oooops its not my fault that wall was live it was the manufacturer, Not sure it will hold any ground in the courts, but have you all noticed these cables are always clear nothing connected and its always there.....

 

[thekingiam]

can't believe you have connected what sounds like a disconnected circuit!
go back please and disconect it, if everything still works leave it disconnected.

 

[Brendan976]

Borrow a tone generator,disconnect from consumer unit, connect generator to the now disconnected ends, turn on to constant tone, now trace where the cables go the louder the tone means the closer you are.
Ben

 

[PEG]

Borrow a tone generator,disconnect from consumer unit, connect generator to the now disconnected ends, turn on to constant tone, now trace where the cables go the louder the tone means the closer you are.
Ben

That's the spirit,Ben,proper use of correct gear but it appears the suggestions of oiling the bolt have arrived a while after the horse left...

 

[Brendan976]

You never know it may help someone else who comes across a similar situation in the future. Or the original op gets a repeat bit of work at the same premises.

Ben

 

[oldtimer]

You never know it may help someone else who comes across a similar situation in the future. Or the original op gets a repeat bit of work at the same premises.

Ben

Brendon sorry to say that aint going to happen as there is repeat posts on the forum and in my opinion its because the OP is to lazy to do a search "Earth Bonding" is a prime example