Inspection of flat. advice please. Immediate Danger?

[brummydave]

Im fairly sure I have a couple of metal bare bones wylex units kicking around if you want to make a forum donation for one.

that's mighty kind sir. bare bones as in no mcbs or no rcds either?

 

[steptoe]

might be a main switch, but Im pretty sure NO RCDs, I'll have a look tomorrow, I have a couple kicking around, how many ways do you need?

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I could probably throw in a few MCBs if you need them, they are fairly common anyways.

 

[brummydave]

With the recent relevations that c/units do not have to be fire proof i will be fitting more metal clad ones. Last one i did in a situation like this was to remove the guts of the old board and mount the new one over the top, thus leaving all the conduits in situ and a nice big joint box if any cables are too short.

One problem with the nice big joint box - is the big hole in the front. one reason it's being changed!

 

[andy_spark]

If you're desperate I changed one of these wylex boards last week, I'm sure the screw on cover is still bouncing around my van at the moment. Let me know if you want it.

 

[brummydave]

If you're desperate I changed one of these wylex boards last week, I'm sure the screw on cover is still bouncing around my van at the moment. Let me know if you want it.

thank you. sounds like a top quick fix... although it'd still be better to fit some sort of RCD protection! So will suggest a planned more leisurely replacement.

 

[brummydave]

Update on this, I spent ages calculating/estimating how long the work would take, detailing my proposals for remedial works etc, and factoring in the rush element to give an estimate of cost. :Neil

Only to be replied with saying they'd already had a quote of nearly half the amount. Grrr! headbang

If they'd given me that ball park figure I would've realised a lot faster to walk away from the job :run

Maybe it's the guy that did the PIR before, so i suspect he'll use cheaper parts, not do any testing etc.

I've suggested as much and also that testing and doing the job properly takes a lot of time. I cheekily mentioned that others would charge double! (what are the MEB Installers called these days?!! E-on? )

Annoying thing is spending time and energy on it all when there's sooo much other work to do!

Lesson learnt, maybe they'll come back to me.

adios.

 

[steptoe]

I get stupid stuff like that all the time Dave,

headbang

 

[brummydave]

They just came back to me!

Would I do the board without a full test to reduce costs?! "It had one last year..."

I'm not comfortable with that, but I guess I could include it on limitations....

 

[steptoe]

Dave,

i do hope you are not seriously contemplating that!?

 

[brummydave]

Dave,i do hope you are not seriously contemplating that!?

In a word, No.

I discussed the probability that a cheaper quote than mine would've gone that route, and the pitfalls that would ensue. Sending the landlord a copy of the ESC's 'landlords guide to electrical safety' was a great move, I think the info in there cemented their decision.

I've talked them into doing everything properly. Whoop!!!

I ended up saying having a new board without testing was like putting new tyres on car that you weren't sure that the engine would go or not. I also likened electric works to a mechanic - when you have a fault with the car you pay them to diagnose it, sometimes strip it down, maybe then know what the full cost would be but often not until the car was back on the road. I think the analogy worked! Trying to price a job before testing is not ideal and I think I got them to see that.

Just gotta find time in packed schedule

 

[steptoe]

I always do a limited PIR before a board change, after a while you will find it wins you more work than it costs you.

 

[Sharpend]

I always do a limited PIR before a board change, after a while you will find it wins you more work than it costs you.

Is that an NIC pir? The visual type or drive by??

 

[steptoe]

no, its to make sure there are no major hidden faults,

 

[brummydave]

Update on this one, did an insulation resistance test on the whole installation and the Line to Earth figure is 1.65MOhm.

Now I know it's above the 1MOhm minimum, but i've never seen an actual reading this low! Was thinking to repeat the test but circuit by circuit this time.

What does everybody else do in this case?

Last september the test results showed 35MOhm. I'm not sure about a load of those test readings, especially as on the lighting circuit r1+r2 was recorded as 0.51 and I got maximum readings of 3.1. , but it still adds to concern as well.

This is all in prep for replacing the board - they've ok'd that but I won't without ironing out probs first!

 

[Andy™]

Now I know it's above the 1MOhm minimum, but i've never seen an actual reading this low! Was thinking to repeat the test but circuit by circuit this time.

im guessing you havent done much fault finding then. low IR is very common. often so low, its better to switch to continuity instead of IR

 

[brummydave]

im guessing you havent done much fault finding then. low IR is very common. often so low, its better to switch to continuity instead of IR

In the grand scheme of things, not really. I've mostly installed. The faults I have found have been things like nail through cable, loose terminations.

The continuity I did first and got ok readings everywhere.... but as it is a mostly steel conduit system (buried) there are parallel earth paths galore!

What else am I missing?

 

[steptoe]

r1 r2 of 3.1

something badly wrong there for a normal 3bed semi, unless its a [very] big flat,!

you might have to downsize your MCB a bit!

 

[brummydave]

r1 r2 of 3.1

something badly wrong there for a normal 3bed semi, unless its a [very] big flat,!

you might have to downsize your MCB a bit!

I was getting readings over 2Ohms at most lighting points.... But as I read table B6 in the OSG, I could go up to a 10A MCB with readings up to 3.71Ohm. So a 6A will defo be fine?

As i've only just back from the place, think i'll let the head rest :z :z

In addition tho, I did find that the insulation readings were fine on all circuits bar one - which was the only circuit not installed in steel conduit 40 years ago!

It's wired in 2.5mm TnE and gave a reading of 1.05MOhm L-N. Methinks there's a problem on that one

There were no shorts tho, and the L-E and N-E were both fine too once disconnected from the board. Will get the socket fronts off next visit.

nightie night. -_-

 

[steptoe]

Its not as simple as just having your readings under the permissible limits Dave,

Are the readings consistent with what the anticipated circuit length is likely to be?

 

[brummydave]

Its not as simple as just having your readings under the permissible limits Dave,

Are the readings consistent with what the anticipated circuit length is likely to be?

I'm not sure, I'm struggling to find values for resistance of steel conduit so working out what I should be getting is tricky!

Will measure lengths tomorrow and go from there....