Electric test fail.

[Phoenix]

surely a socket on each end and a short length of flex with 2x plugs would have been easier?

Stop giving the plumbers ideas!

 

[daveg]

I had another electrician look at the problem last week when the flat was empty. This is what he reported:-

Carried out a fault find to the circuits as requested to find the location of the break in the ring main, we removed every socket in the kitchen area where the circuit is for ad inspected ever fuse spur to make sure the wiring configuration was correct, which it was. To shared load balancing we have now installed what was the ring main when previously tested by someone else onto x2 20amp MCBs giving the circuit a total of 40amps in the kitchen which is more than sufficient. We are led to believe that the previous ring readings were incorrect.

If I understand what he is saying is there was no break in the ring circuit and the guy doing the EICR made a mistake. The ring now has a 20A MCB at either end. Does this sound right?

 

[michael8554]

He didn't test for a break, he just looked for a loose connection or incorrect connection in every socket.
Having taken every socket off the wall it would have been easy to diss the wires and check the wiring for continuity between adjacent boxes.
With the ring broken at the CU of course.
And so find between which two sockets the break was.
If there ever was a break of course.

 

[Andy™]

i really hope they didn't stick each end of a ring onto different 20a breakers...

 

[michael8554]

To me that's how it reads.
They assume there's a break and so make it into 2 spurs ?

 

[Fleeting]

To me that's how it reads.
They assume there's a break and so make it into 2 spurs ?

They should have established where the apparent break was by testing.

 

[Richard-the-Ninth]

daveg, have you got something simple such as a table lamp / mains powered radio?

I was going to suggest you plug it in, in the kitchen, switch it on, and then turn off one 20A mcb does the "device" stop?
If it doesn't switch the 20A mcb back on, and switch the other mcb off, same question.
If it does not stop with either 20A mcb is switched off, switch them both off, same question.

(We are all wondering the same thing, this way we can find out.)

 

[daveg]

Thanks for the replies. Is the latest electrician saying it IS a broken ring main? The flat is 260 miles away and I was going to go and look at it if the letting agent couldn't find an electrician - it doesn't seem difficult to find which two sockets the break was between. If they took every socket off and looked at the number of wires in each wouldn't it be obvious if it wasn't wired as a ring main? I need to check with the letting agent but I am wondering if they have used the same electrician that did the EICR and when he reports "We are led to believe that the previous ring readings were incorrect." he is referring to the EICR done 5 years ago.

I told the letting agent that I was worried with a 20A breaker if the kettle, toaster, hob and oven were all on at the same time a 20A MCB might trip and it needed looking at. To say sic "To shared load balancing we have now installed what was the ring main when previously tested by someone else onto x2 20amp MCBs giving the circuit a total of 40amps in the kitchen which is more than sufficient." is of no help if he doesn't know where the break is - it may be in the return from the last socket to the CU.

 

[Fleeting]

There may not be a break, it might never have been a ring final but it is easy to establish by testing.

 

[Andy™]

exactly. could be anything. think you need a better electrician

 

[SPECIAL LOCATION]

I had another electrician look at the problem last week when the flat was empty. This is what he reported:-

Carried out a fault find to the circuits as requested to find the location of the break in the ring main, we removed every socket in the kitchen area where the circuit is for ad inspected ever fuse spur to make sure the wiring configuration was correct, which it was. To shared load balancing we have now installed what was the ring main when previously tested by someone else onto x2 20amp MCBs giving the circuit a total of 40amps in the kitchen which is more than sufficient. We are led to believe that the previous ring readings were incorrect.

If I understand what he is saying is there was no break in the ring circuit and the guy doing the EICR made a mistake. The ring now has a 20A MCB at either end. Does this sound right?

You cannot have a ring with two 20A MCB's at each end..

A ring circuit is ALWAYS supplied from the same MCB/RCBO/FUSE etc..

If they have opened up every accessory and discovered it is actually two radial circuits then yes they could be put onto two 20A MCBs.. But the wording is a bit vague..?

Very simple continuity tests can quickly confirm the exact order that all sockets on a circuit are connected..

All sockets on the ring would have at least two cables, (possibly three if there is a spur off the ring at that point).

If you then find a socket with only one cable, it is either the end of a spur off a ring... or the end of a radial circuit..

If there is a broken ring you will either find a loose cable termination at one accessory or find two sockets with cables that appear to go no-where that you cannot find the other end to?

a 20A radial circuit can be sufficient for many rooms in a typical domestic property; e.g. lounge, dining, bedrooms, study... But kitchens / utilities are the areas where I would expect a 32A ring is the best design solution..

There is nothing within BS7671 to say that a kitchen/utility cannot have sockets supplied from radial circuits... However generally kitchens/utilities and radials are not good compatible bed-fellows in my opinion... as these are the rooms where the majority of higher power appliances are used... and you are just asking for a potential relationship breakdown with problems later on!!

Whilst the hob/oven are probably off a separate "Cooker circuit" you have no control if too many other appliances are using sockets on the same radial.. e.g. Kettle / Toaster / Microwave / Washing machine / Bread machine / Iron / Sandwich toaster / Coffee machine / etc.. etc.. which various permutations of, could cause issues..!

It is possible that the electrician has now rectified an error of two 2.5mm radial branches previously sharing a 32A MCB.. and now it is split onto two 20A MCB's.. But not 100% sure from the description in your quoted report text??

Personally If I had been asked to undertake this work I would have provided a sketch layout of rough socket positions on an approximate room plan layout with simple "join the dots" type lines showing the order that the various sockets / accessories are connected... and/or where any ring break / radial circuits end.

e.g. a current job (kitchen refurb), which is being ripped out tomorrow and Thursday I will be visiting to amend wiring ready for fitters to commence on Friday.. But a couple of weeks back I did a few preliminary investigations so I know exactly how the current circuit is wired..
Which also identified a spur off a spur on the island unit to be resolved.. My blue numbers in circles are the number of cables at that accessory and red numbers are earth loop impedance values, (its a TT installation hence higher earth loop values).


This level of testing, investigation, identification, of a circuits composition is the most basic and simple tasks for a competent electrician to perform...

I cannot see how anyone could confuse a "broken ring" with two "radials"??
Unless someone is actually incompetent??

 

[ProDave]

i really hope they didn't stick each end of a ring onto different 20a breakers...

I once found just that. A house with a shiny new CU but no labels. I had to do some alterations to a socket circuit, so I went through all the unlabelled mcb's one at a time, and none isolated my circuit. Further investigation revealed that each end of the ring was connected to a 32A MCB.

Nobody seemed to know anything about who had fitted the shiny new CU.

 

[Geoff1946]

Some years ago a friend asked me to look at his installation because he couldn't turn off the sockets without using the main switch. It was a brand new house. The ends of the ring ring were wired to two 32 amp mcbs, one of them shared with the cooker. They had simply confused the cooker feed and one end of the ring.

 

[Murdoch]

Did an EICR on a 1950’s house last year

Ring circuit one leg in the 30A and the other in the immersion 15A, and the immersion in the 30A

My guess was that it had been like that since built

 

[ProDave]

They had simply confused the cooker feed and one end of the ring.

And failed to do any testing of the installation.