clever ways of ring final test without removing spur fronts??

[Sparksaflyin]

Morning fellas. I know from regular visits to this website that we have some rather intuitive Sparkie’s on here so I thought I’d join in the fun.
I’ve got a rather basic question to start with but also where some of you can hopefully show your tips and tricks.

Im currently working on a project, making pre fab elec cupboards. These cupboards only have 1 circuit on the fuse board, until this is added to on site. The circuit consists of 17 points, only 3 of which are sockets, the rest being switched fused spurs and only 7 of these have loads installed in the factory. I do all the dead tests at source but unfortunately I don’t do all the installation as there are 5 other “Sparkie’s” (use the term loosely) on site. It’s becoming rather a pain removing all the spur fronts to do my ring final test, fully and properly. Now I’m more than willing to accept that I am being dumb, which I’m sure a few of you will be more than willing to point out, but do you guys have any ideas as to short cuts I could use to make the whole process a lot quicker?

Any ideas, opinions, legal short cuts welcome.

Thanks fellas.

This is my first post as well so hopefully it’s not too brutal an introduction. cheers boys!

 

[telectrix]

I assume you want to test R1+R2 (and Zs) at each Spur. the only way would be to get your readings before screwing up the faceplates, IMO.

 

[Octopus]

A ring with 17 points - of which only 3 are sockets ........ sounds odd to say the least.

 

[Sparksaflyin]

Not the only odd feature of this particular install I might add! Designed by, lets call them, non Sparkie’s.

It will literally just be R1 + R2 and polarity. No live testing. This will be carried out on site once unit is powered up. My tests are literally to confirm cable wiring and insulation are correct before the units leave the factory. I’ve been told to just test the sockets but I’m not prepared to do this as it does not confirm polarity is correct at any of the remaining 14 spurs.

 

[Richard Burns]

Welcome to posting on the forum.
Initially I am think electric screwdriver for speed, but you probably already do that.
If you can get to the cupboard earlier in the assembly so that the spurs are wired but not fixed back yet and do, perhaps, just the ring continuities this may work.
If you have loads attached then on some loads it is easier to get to the connections at the load end and you can then take account of the resistance of the supply cable (which should be minimal in your case).
If the spurs are all the same and you know where the terminals are and this is a repetitive task then you could make up a custom test probe bracket that can automatically access the terminals when the spur is just pulled a short way from the wall, but you may find getting the probes in the right place slower than taking it off entirely.

 

[telectrix]

just awaiting Megger's invention of a wireless probe system. just put a fob in close proximity of the spur and the new MFT will give a wi-fi read out of all you need. then the fob on your ipad can read off the MFT and enter the readings on the EIC. happy days.

 

[KentSparky]

Not the only odd feature of this particular install I might add! Designed by, lets call them, non Sparkie’s.

It will literally just be R1 + R2 and polarity. No live testing. This will be carried out on site once unit is powered up. My tests are literally to confirm cable wiring and insulation are correct before the units leave the factory. I’ve been told to just test the sockets but I’m not prepared to do this as it does not confirm polarity is correct at any of the remaining 14 spurs.

If you have been told to only test the sockets then I am baffled why you are not happy to do this? Just make a note on the certificate that you have only tested the sockets ,or have I misunderstood?

 

[shaun1]

Can you get to the live terminal by popping the fuse out and sticking a prove in to the fuse holder? And the earth via a faceplate screw? That would give you R1 R2. The resistance might be slightly higher through the screw though so you would have to compare.

EDIT: Actually, thinking about it, im not sure if the fuse holder stops you accessing the actual live part behind

 

[Sparksaflyin]

Thanks for the responses. Keep them coming. I like your way of thinking.
Unfortunately the people telling me to just test the sockets have absolutely no idea of the reason behind testing and the implications of getting it wrong or not doing a thorough job. They are plumbers, need I say anymore. They’ve got the contract for these utility pods because they also contain a boiler. As I said in previous message, just testing the sockets isn’t going to give me any indication as to the correct polarity of the spurs. I currently whip them off with a battery screwdriver and to be honest it doesn’t take me too long it’s just an inconvenience rather than a flat out problem. Testing via the fuse carrier and screw isn’t an option as it’s a plastic dado trunking system so there are no earthed metal back boxes to get a reading off. Testing the load side is an option but like I say this is only 50% of the spurs that have a load fitted, the other 50% being installed when they go out to site. I guess I’m just being lazy and will need to continue with the old fashioned way. I’m always looking for more productive ways of doing things but I guess sometimes there just isn’t one.

 

[Sparksaflyin]

Actually now I think about it the screw will have a connection to Earth regardless of the metal back box, so your way may be plausible, providing there is a good connection to the line conductor via the fuse carrier. I’ll give it a go tomorrow and see what it comes back with. It may be a slightly higher r1+r2 reading but one thing it will confirm is correct polarity. Top marks for that man!

 

[Octopus]

Is anything connected to these fused spurs?

 

[Sparksaflyin]

No they are currently just flex’s coming out to final position which I’m aware I can just test the ends of and deduct the overall resistance of the flex from final r1 + r2. It’s more the spurs that have no loads/flex’s connected that I’m concerned with

 

[Richard Burns]

Can you tell production not to screw the face plates into position just leave the screws attached to the face plates; Once testing is completed you can then put them on only rather than both on and off and would speed up production further back in the line as well.

 

[Octopus]

No they are currently just flex’s coming out to final position which I’m aware I can just test the ends of and deduct the overall resistance of the flex from final r1 + r2. It’s more the spurs that have no loads/flex’s connected that I’m concerned with

How long are the flexes?

 

[Sparksaflyin]

I could do mate yeah, it’s just some of the people we are working with really couldn’t even be called Sparkie’s and that’s without even mentioning the plumbers! There’s a couple of flexes that would have negligible impedance so could be disregarded entirely to be fair but there’s also a couple of 4/5 metre ones that would just need deducting from reading

 

[Sparksaflyin]

To be honest it’s not a great hardship to continue what I’m doing but like I say I’m always looking for ways to be more productive so I thought someone may have thought of an intuitive way to overcome it

 

[gazdkw82]

Actually now I think about it the screw will have a connection to Earth regardless of the metal back box, so your way may be plausible, providing there is a good connection to the line conductor via the fuse carrier. I’ll give it a go tomorrow and see what it comes back with. It may be a slightly higher r1+r2 reading but one thing it will confirm is correct polarity. Top marks for that man!

I always use an exposed conductive part to gain a Zs reading. It proves the exposed metal work is earthed and also provided the highest value Zs likely to be present on the circuit.

 

[Sparksaflyin]

Yeah that makes perfect sense gaz and to be fair should probably be the industry standard

 

[johnduffell]

If you have been told to only test the sockets then I am baffled why you are not happy to do this? Just make a note on the certificate that you have only tested the sockets ,or have I misunderstood?

Electrician is a professional job so you have to take responsibility for doing things right sometimes. You answer to professional responsibility as well as the customer

 

[Sparksaflyin]

My point of view exactly John. If we don’t do things responsibly and properly, people die.