minor works testing

what testing are you doing for a like for like replacement. (im newly qualified)

e.g replacing over sink instant water heater 3kw. (bearing in mind my company do not want us testing and say its just maintenance, so they have not provided test equipment) but i think all work should be tested.

i have recently replaced one, its in an old building fed from a DB that can not be fully isolated. i can isolate the water heater circuit but can not isolate full board to do dead tests. it is fed to a fused spur then flex to the water heater.  i have changed the fused spur to an RCD fused spur.

if i could isolate the whole board i would do the following tests, continuity,  insulation, polaity, loop test(though i would just calculate this having done R1+R2) and RCD. 

since i can not, am i ok in to just to do Zs and RCD test and explain on the sheet why? (as long as previous paper work is to hand with Zs readings etc)

You can do an R1+R2 without isolating the whole board. And you can do an IR test on the cable to the water heater (depending on the design of the board if it's safe to remove the N for that circuit while the rest of the board is still live) And what's stopping you confirming polarity?

You can do a loop impedance test on the supply (which needs it on anyway) so there you have Zs

Granted those will be a bit of a ****** to do if they haven't given you any test equipment, but then you won't be able to prove dead so won't be able to do any work then will you?

Tell them to give you the tools to do the job properly.

by installing an rcd fcu, 132.16 comes into play, so earthing and bonding needs to be checked. You would also definitely need to do rcd tests on it. Why install an rcd fcu?

Unfortunately Dave, as I'm sure you know from experience, many of these large companies and some smaller ones do not provide each electrician with a test kit, it's just a shame that the scams that they register too don't take our industry a little more seriously. Is it not a fundamental basic requirement to carry out said tests prior to working on and prior to re-energising a circuit. I thought that was what the assessor looks for, it sure seems to be a big deal when I was learning the trade? 

Thanks for the reply.

sorry im not making myself clear.  I have my own volatge indicator, proving unit etc so safe isolation is no problem

what i mean is i dont have a multi function tester to complete a full set of tests.  i have my own continuity/insulation tester. so can do them no problem.  just confused on how to do the dead tests without isolating the board?

Yes i can confirm polarity no problem. and i can def complete all tests stated from the fused spur to water heater just not from board to fused spur (i thought the whole board would need isolating to complete dead tests (all through my training this is what i did) how would i do these dead tests not being able to isolate the main board?

hope im a bit more clear now

Rob_the_rich said:

by installing an rcd fcu, 132.16 comes into play, so earthing and bonding needs to be checked. You would also definitely need to do rcd tests on it. Why install an rcd fcu?

Click to expand...

thanks rob

manufacture instructions. must be RCD protected.

you could just do R2 on the feed to the fcu with a wander lead. You wouldn't be able to calculate Zs from R1+R2 without Ze anyway.

But I can't see how you can do IR test without safely isolating the DB and removing the N. Why can't it be isolated?

I suppose you could put it down as an agreed limitation and pass the buck to your Qualified Supervisor, who you should really ask for their opinion anyway, since they will also have to sign the cert.

Another thought is to install an rcd between the appliance and the fcu, that way you are working on a circuit protected by the 13A bs 1362 fuse and would only need to test that part of the circuit.

Rob_the_rich said:

you could just do R2 on the feed to the fcu with a wander lead. You wouldn't be able to calculate Zs from R1+R2 without Ze anyway.

But I can't see how you can do IR test without safely isolating the DB and removing the N. Why can't it be isolated?

I suppose you could put it down as an agreed limitation and pass the buck to your Qualified Supervisor, who you should really ask for their opinion anyway, since they will also have to sign the cert.

Another thought is to install an rcd between the appliance and the fcu, that way you are working on a circuit protected by the 13A bs 1362 fuse and would only need to test that part of the circuit.

Click to expand...

thanks Rob.

wander lead could be an option this time (sometimes the boards are to far away) though i dont have one.  i would just use the ze for the type od sytem i.e TN-S etc.  Im working on very old buildings with various things going on all the time, only time i would be able to isolate full boards would be out of hours (that is not going to happen).  there is no certs for anyone to sign! thats the point, im doing all this off my own back with no support from my company (who class all my work as maintenance that does not need testing) No chance of installing an RCD between Fused spur and board, old building very awkward to get anything done really. also i would still need to test the full circuit as i have installed the rcd so i would be in the same spot really.  

ill just be getting certs from on line and keeping them for my own personal reassurance.

what my company does with new installs, is get us to do the work then get an outside company to test, which is fine because when they want new installs i get the support needed (so i can isolate, test what i can etc) its just with this grey area im not getting the support as said above about being maintenance/like for like etc. 

Hi Sparkingmad ,

Welcome to the Forum & stay with us.

I presume that when training / college etc you had to isolate boards for H&S reasons .

I may be picked up on this but in the REAL world , say at industrial premises, you can't go isolating boards & shutting down half the factory while you pull a fuse  etc.  

You could do the "Dead" test on a live board ...just switch off the breaker  or pull the fuse , disc. the N & Megger it .   Earth the L in the breaker  ( with it OFF)  & read R1+R2   at the heater.

As far as I know , we all work on live boards & panels as part of our job ....or am I a dinosaur wallowing in a time-warp & wondering where all the other dinosaurs have gone  ?

I congratulate you for trying to do the job right ....AND ...you raise an interesting point for further discussion..... large contractors , by their very nature , are not going to have ,say,  twenty Fluke  multi-testers  , one for each operative .

I know whats coming .....the supervisor will turn up just as you finish connecting the heater with the tester and do it all and certify ................yeah !  Like hell he will !!

Thing is , you are doing the job to the best of your ability but cannot actually verify that the heater is  earthed properly .

Pehaps you should write on your time sheets ....installation not tested due to lack of instruments.

If they are an NICEIC  contractor ,say,  they should have picked that up by now. I think its your supervisor's problem however , not yours.

thanks evans

yep all my training was done with health and safety paramount but as you say its not realistic in the real world at all times, im confident in my abilities to be able to do as you say above just ive never done it before hence my question, see all my testing has been done on new installs and circuits i could safely isolate, suppose the real learning curve is the periodic/condition report side of testing when it comes down to the electrician to decide what is to be done and whats not!

Question 

If i decide that via risk assessment that its not safe to complete the dead tests on a live board and that im happy with Zs, polarity and RCD test for the whole circuit, then complete the full range of tests (con,IR etc) from the part of the circuit i have touched i.e the flex from Fused spur to heater. would this be sufficient to cover my back? 

hope you can understand that ha.

I would ask my guys in this circumstance to verify bonding was in place. R1+R2, Zs and RCD testing if necessary. 

thanks essex.

could you take me through how you would complete the R1+R2 on the live board.

thanks.

sparking mad said:

thanks essex.

could you take me through how you would complete the R1+R2 on the live board.

thanks.

Click to expand...

R1 (the phase conductor) is already isolated by virtue of turning off it's mcb. So remove it from the mcb.

R2, the CPC can be disconnected from the earth bar.

you now have both conductors you are wanting to test isolated, so what is stopping you from doing your R1+R2 test while the rest of the board remains live? is it just you were taught not to do that?

As I said previously depending on the design of the board it may or nay not be safe to access the neutral bar. but if it's a board with good access, and you can positively identify the correct N wire, and it's not sharing a terminal with another circuit, then there is nothing stopping you removing that as well and doing a proper IR test on all conductors of that circuit.

Like others have said, go into an office block, with a fully loaded 3 phase board with your objective being to change one broken socket, and see the reaction you get when you say you want to shut off the whole lot...........

ProDave said:

R1 (the phase conductor) is already isolated by virtue of turning off it's mcb. So remove it from the mcb.

R2, the CPC can be disconnected from the earth bar.

you now have both conductors you are wanting to test isolated, so what is stopping you from doing your R1+R2 test while the rest of the board remains live? is it just you were taught not to do that?

Some of the boards are 3 phase with a lot going on and im a bit nervous of sticking my fingers in to be honest! the one im working at the min is single phase and should be doable so i will have a go ha, yes being taught not to do something does play on my mind also, though thats something i will just have to get over!

As I said previously depending on the design of the board it may or nay not be safe to access the neutral bar. but if it's a board with good access, and you can positively identify the correct N wire, and it's not sharing a terminal with another circuit, then there is nothing stopping you removing that as well and doing a proper IR test on all conductors of that circuit.

Like others have said, go into an office block, with a fully loaded 3 phase board with your objective being to change one broken socket, and see the reaction you get when you say you want to shut off the whole lot...........

yes this is not a good situation, though i would not be as concerned to test just for a socket face (this im happy to class as like for like) 

Click to expand...

thanks for the reply.

in bold above

Sharpend said:

Unfortunately Dave, as I'm sure you know from experience, many of these large companies and some smaller ones do not provide each electrician with a test kit, it's just a shame that the scams that they register too don't take our industry a little more seriously. Is it not a fundamental basic requirement to carry out said tests prior to working on and prior to re-energising a circuit. I thought that was what the assessor looks for, it sure seems to be a big deal when I was learning the trade? 

Click to expand...

No I didn't know that. When I worked for a big firm they provided us with all the kit.  Now I am self employed of course I have all my own test kit.  I wouldn't dream of doing electrical repairs and alterations if all I had was a "voltage proving kit"  That's only 1 step up from a DIYer who only has a neon screwdriver

At least in this case the OP appears to have his own kit, even if his employer is too tight to provide it for him.

Sparking  Mad   there are a lot of problems that arise when trying to do what you ask. 

I'll say first up that in my opinion , if you lack the experience , do not try testing  etc on a really old  TPN board  , the actual fuse ones .

Almost certainly you won't be able to identify the neutrals & earths for your circuit  even if the L is marked up .

And in that case I'd have to say to your boss , if you want it testing , you come & do it , because you'll be dropping circuits out all over the place , computers crashing , machines suddenly single phasing ...lights suddenly coing out . Those things are NEVER marked up correctly.

On a modern board , ( they were designed with testing in mind)  you can do it .

sparking mad said:

 ..No chance of installing an RCD between Fused spur and board, ..

Click to expand...

no, between fused spur and appliance. An rcd in an enclosure. That way the circuit you are working on starts at the fcu and ends at the appliance.

Did you supply the new heater? If your company supplied it, get them to supply one without the requirement to install an rcd (if one exists, I can't find one after a quick search). Do they know you are fitting RCDs?

The whole situation seems really poor TBH.

Rob_the_rich said:

no, between fused spur and appliance. An rcd in an enclosure. That way the circuit you are working on starts at the fcu and ends at the appliance.

Did you supply the new heater? If your company supplied it, get them to supply one without the requirement to install an rcd (if one exists, I can't find one after a quick search). Do they know you are fitting RCDs?

The whole situation seems really poor TBH.

Click to expand...

 ah ok mate, physically not enough space for this.

yes i supplied the new heater, this is the only heater our preferred supplier uses now.  i think most instant water heaters over 2kw have to be RCD protected.  No they do not know but they will as im brining it up with my supervisor after the break. we do not have an RCD tester! ha.

Ive decide to install it to standards then im going to isolate it, lock and tag off until they get someone to test it or give me the equipment to test it.  then at least ive done my job and the balls in there court.

Evans Electric said:

Sparking  Mad   there are a lot of problems that arise when trying to do what you ask. 

I'll say first up that in my opinion , if you lack the experience , do not try testing  etc on a really old  TPN board  , the actual fuse ones .

Almost certainly you won't be able to identify the neutrals & earths for your circuit  even if the L is marked up .

And in that case I'd have to say to your boss , if you want it testing , you come & do it , because you'll be dropping circuits out all over the place , computers crashing , machines suddenly single phasing ...lights suddenly coing out . Those things are NEVER marked up correctly.

On a modern board , ( they were designed with testing in mind)  you can do it .

Click to expand...

thanks evans

yes i am not experienced enough on the condition report side of testing, im going to put myself through the 2394 and maybe 95 to get some extra experience. (my company wont put me through it, already asked)

sparking mad said:

 yes i supplied the new heater, this is the only heater our preferred supplier uses now.

 we do not have an RCD tester! ha.

 im going to isolate it, lock and tag off until they get someone to test it or give me the equipment to test it.

Click to expand...

Are you an employee or self emplyed?  YOU supplying the materials doers not sound right if you are employed.

No RCD tester, what none in the whole company? never.

So you are going to leave the circuit locked out until tested. Good for you, the complaints from the customer might kick your employer into doing something.