continuity tester and proving unit also required?

[Ziggie]

The conversation has fired off a conversation I had some time ago.
Someone stated that it is difficult to get a qualified person to sign of the work. I can understand that they would prefer to do the work to earn the money.
As this is a “legal “ requirement for some work , the need for a must do on request and fixed pricing policy should be required by law.
An example of this is London taxi drivers who are not allowed to refuse a journey within central London and the meter is legally controlled and standardised.

 

[Ziggie]

haggis???? i'd rather chew on a michelin ZX.

It’s in the post if you record the video

 

[pc1966]

Even if you stick to doing simpler DIY electrics it is a very good idea to have a proper voltage tester. I always advise getting the simple sort that don't need a battery - they do the key job and if you come vback t it after a couple of years it is not corroded inside because you forgot to remove the battery...

Something like this, for example:
https://www.screwfix.com/p/lap-ms8922b-2-pole-voltage-tester-with-rcd/669hy
https://www.cef.co.uk/catalogue/products/4527406-voltage-tester

As mentioned above, the process of "proving dead" is drilled in to trainees to make sure that it is not a medic proving them dead later on! Basically you check the tester, check all the permutations of cables that could be live (always connecting first to the most likely to be deal line, which initially would be the earth/CPC), and finally check the tester once more. Also you need to take steps to ensure it won't be accidentally switched on either!

A proving unit is handy for this as it is safe, available even when you think power is off, and usually the step up in voltage so you also see if the tester's range-indication is reasonable. For example:
https://www.cef.co.uk/catalogue/products/4457482-proving-unit

Getting a MFT is quite an investment, as said above it is hard to justify for sorting out a handful of sockets compared to what a professional electrician would charge simply to do the job.

You might find the high loop impedance is down to a handful of poor connections at the backs of sockets and simple to fix without a rewire, or you might be unlucky and find the poor connections are in hidden junction boxes.

 

[richy3333]

Fill it with quick dry cement , wrap it in some old carpet and bury in the ground...and NEVER speak about this ever again....

I don't think it's notifiable in Scotland, because I'd be replacing an existing circuit. [1]

However, I take your point it's a huge job, which is presumably why it's notifiable in England, and maybe in other parts of the UK and the world.

Maybe as you suggest, I should get a sparky involved. At the very least for certification, but realistically sounds like you're saying for the whole job.

You may need a building warrant but there isn’t enough info to comment.

No registered spark in Scotland will let you do the work and then sign it off. Protected title is going through government for a reason

 

[inquisitive]

I admire your interest and enthusiasm. I would suggest maybe reading a decent book on inspection and test, and maybe also Guidance Note 3 from the IET.

You need to be sure of your abilities and understanding before shelling out several hundred pounds on a tester that you may not end up being able to use properly.

Thanks, that's some concrete reading, for me to have a start with—which I would have to master.

You make a really sensible point about not spending large amounts of money on equipment, unless and until I do gain that understanding.

a proving unit used used to ascertain the performance of a safe isolation tool, which is basiaclly a 2 prong voltage tester.
View attachment 61832
this is totally different from a multifunction tester which,as it's name means, can perform several essential testes.
View attachment 61833

Good point. Have just re-read the OP's initial post and there does seem some confusion.

Yes, so leaving aside the proving unit, we are at the heart of my confusion.

As far as I can tell from the data sheet, that Megger MFT1721 multifunction tester, it has a mode for testing continuity. This mode displays the value of the live voltage if there is one. So why do other people who buy a multifunction tester also seem to buy a separate two prong tester, like the pictured Kewtech?

Possibly I completely misunderstand the functions of the multifunction tester. Or maybe the multifunction tester has the functionality, but people prefer having a standalong two prong voltage tester. If so, why is that? Maybe because it's smaller and lighter? Or maybe because the interface is simpler in a standalone two prong voltage tester - simple leds, and no dial that you have to set to the correct mode?

 

[telectrix]

basically you 2 prong voltage tester measures the vols across the 2 prongs, either with LEDs or a LCD readout.nothing more. it's to test for live or dead. some do have the additional function of continuity measurement and.or phase sequence. on the other hand, a MFT will measure voltage/continuity/ loop impedance/insulation resistance-breakdown/RCD trip times/ and can download readings to a laptop. differny kettle of squid, as in hundreds of ££££.

 

[Flanders]

My question would be . Does the circuits need rewiring there could be a number of ways to rectify a high earth loop reading

 

[pc1966]

Basically a voltage tester does one job and does it in a safe and reliable manner.

You can use other means of checking if a cable is live but you have a far higher chance of a mistake costing your life. The most common thing that folk might try to use is a multimeter, and there you have the following possibilities:

• Use AC volts, meter working = you live
• Use DC volts = you die as it read near-zero on 230V AC
• Use amps or ohms and it is CAT III+ rated = you die if you did not notice the fuse blowing and it failed to show 230V
• Use amps or ohms and it is cheap meter = you die or are seriously injured in a ball of flames as the meter explodes

When it comes to proving dead you must not make any mistakes, so go with the simplest, most reliable, and safe tester you can get.

 

[dodger421]

Possibly I completely misunderstand the functions of the multifunction tester. Or maybe the multifunction tester has the functionality, but people prefer having a standalong two prong voltage tester. If so, why is that? Maybe because it's smaller and lighter? Or maybe because the interface is simpler in a standalone two prong voltage tester - simple leds, and no dial that you have to set to the correct mode?

Simply put, it’s about using the right tool for the job. Learning which tool to use is what takes the time and is part of the reason there’s so much HSE training on electrical courses.

HSE GS38 tells us what standards our equipment has to meet under the EAWR and outlines why you should use an Approved Voltage Indicator and not MFTs or multimeters for measuring live voltage. Not only does it help you comply with the EAWR, following it keeps you and the people around you alive.

Also, continuity testing is a dead test, there shouldn’t be any voltage present. The MFT displays or indicates voltage if it detects it because it represents a dangerous situation and it’s warning you to do something about it. Some don’t give a measurement, just beep at you and flash a warning symbol or colour, all should inhibit continuity testing while voltage is present.

 

[telectrix]

Some don’t give a measurement, just beep at you and flash a warning symbol or colour, all should inhibit continuity testing while voltage is present.

mine bleeps and show a hammer symbol. the manual tells me that this means to chuck a hammer at the main switch

 

[inquisitive]

My question would be . Does the circuits need rewiring there could be a number of ways to rectify a high earth loop reading

Fair question. I am being pessimistic, because the sparky was. But the first port of call is could be (?) replacing the faceplate, ensuring the screws are tight, etc.

 

[inquisitive]

Even if you stick to doing simpler DIY electrics it is a very good idea to have a proper voltage tester. I always advise getting the simple sort that don't need a battery - they do the key job and if you come vback t it after a couple of years it is not corroded inside because you forgot to remove the battery...

Ah, thanks for these recommendations. I didn't see your post originally, but I always like concrete recommendations.

Getting a MFT is quite an investment, as said above it is hard to justify for sorting out a handful of sockets compared to what a professional electrician would charge simply to do the job.

You might find the high loop impedance is down to a handful of poor connections at the backs of sockets and simple to fix without a rewire, or you might be unlucky and find the poor connections are in hidden junction boxes.

Thanks, that's some useful perspective. Sometimes I get way too into DIY, probably to make up for not being enough into it, in the past. But it's always easier, at a certain point, cheaper, to hire a pro.

[...] .nothing more. it's to test for live or dead. [...] differny kettle of squid

Basically a voltage tester does one job and does it in a safe and reliable manner.

You can use other means of checking if a cable is live but you have a far higher chance of a mistake costing your life [...]

Simply put, it’s about using the right tool for the job. Learning which tool to use is what takes the time and is part of the reason there’s so much HSE training on electrical courses.

HSE GS38 tells us what standards our equipment has to meet under the EAWR and outlines why you should use an Approved Voltage Indicator and not MFTs or multimeters for measuring live voltage. Not only does it help you comply with the EAWR, following it keeps you and the people around you alive.

Ah! Thanks all, this is really sound advice, well explained. These are life saving devices. The easier they are to use, and the harder they are to misuse, the safer you'll be.

I also see the paragraph (19) in HSE GS38, where it advises against multimeters for dead testing. With what you've all been saying, I now see how it's also advising against multifunction testers, when dead testing.

 

[dodger421]

I also see the paragraph (19) in HSE GS38, where it advises against multimeters for dead testing. With what you've all been saying, I now see how it's also advising against multifunction testers, when dead testing.

Testing for dead and dead testing are two very different things. An MFT is essential for one and not recommended for the other.

If you want to learn more I strongly suggest looking into some formal training at a local college or other learning provider. Electricity can and does kill, the risks of something going wrong increase dramatically the less experience and training you have. Inspection and testing is not something you can safely learn by just watching a few YouTube videos and going off to experiment.

 

[Flanders]

Fair question. I am being pessimistic, because the sparky was. But the first port of call is could be (?) replacing the faceplate, ensuring the screws are tight, etc.

It all depends ,the high reading could be to courses by a poor connection, a damaged cable or poor design. Do you know what the high reading was ?

 

[pc1966]

Sometimes the CPC (earth) is going to the back boxes and not the sockets' E terminal, and generally poor connections via faceplate screws lead to high R. Of course it should never be wired that way!

Also an open CPC on a ring (i.e. incomplete ring) can lead to high-ish R at the end socket where the break occurs, at least compared to what the ring was designed for.

That is where the MFT measurement helps of course, but if it is not an obvious fix like cleaning/tightening joints or replacing suspect sockets then you as still far cheaper and safer to get a professional in to do it.