Earth Loop Impedence Test Equipment

[Dave_Conway]

Brains wrote:Has anyone looked at installation testers by a company called Metrel?

Brains, which model number are you using ?

Dave.

[Brains]

Re: Earth Loop Impedence Test Equipment

Dave

I’m using an Instaltest 61557. I also have the remote probe which saves having three hands (great when testing earth fault loop at cooker / oven terminals!!)

Regards

Michael

[Dave_Conway]

Re: Earth Loop Impedence Test Equipment

Brains wrote:I’m using an Instaltest 61557.

How much have you paid for one of these ? I checked a couple of online places and they are about £700 😯

Dave.

[Brains]

Re: Earth Loop Impedence Test Equipment

Dave

Latest price is about £750 plus VAT. If a number of people are interested & we can work up a quantity I may be able to get a discount. I got mine heavily discounted on a special deal at the time I purchased it (less than £600 inc VAT).

😀

[Dave_Conway]

Re: Earth Loop Impedence Test Equipment

Dave_Conway wrote:I’ll get back to this soon.

I did, after a reminder, thanks Lawrence 😉

Robin KMP4120 is £309 in 5’s and £299.10 in 10’s. This has the d-lock feature to stop it taking the rcd’s out. I also mailed http://www.test-hire.co.uk/ to see if they come up with anything on this model and the KMP4116 as well.

More soon 8)

Dave.

[Lawrence]

Re: Earth Loop Impedence Test Equipment

Dave_Conway wrote:

Robin KMP4120 is £309 in 5’s and £299.10 in 10’s.

Either price I want one

Lawrence

[sumphose]

Re: Earth Loop Impedence Test Equipment

Instaltest 61557 is a very good meter. Does everything you would want,but a bit bulky and expensive.
I have been using this unit myself for about 11 months. It is quite complicated to use or understand at first. I would say the robin units are more suitable, and simple meters to work. Best kept for those with a very good understanding of testing procedures and principles.
s 😯

[Brains]

Re: Earth Loop Impedence Test Equipment

Martin

Earth loop impedance gives an indication of the impedance under short circuit conditions between phase & earth. This value is important since if it is too high, the controlling fuse or MCB will not trip under a fault condition.

The limiting values are often dependent on the type of fuse or MCB used. Disconnection time requirements as declared by BS7671 (IEE Wiring Regulations) will also dictate Earth Fault Loop Impedance.

The max values are listed in this very weighty document. Also take a look at the IEE site guide.

Also take care when testing circuits controlled by RCDs. They will trip & you will need to use a range specifically designed for RCD controlled circuits.

Let me know if you need any further help.

Good luck with your tester.

Regards

Michael

[Brains]

Re: Earth Loop Impedence Test Equipment

Martin

This is the mis-understanding that most people have. If you don’t have a means of comparing obtained value vs the listed max value, then taking these measurements are a waste of time (please don’t take this the wrong way). You also need to be careful as inappropriate testing can damage an installation or cause inadvertent shock risks to customers whilst carrying out the test.

Robin publish a little booklet called ‘A guide to 16th Edition Testing’. You should be able to get this from any good wholesaler who stocks Robin Instruments. Also, for a user guide on your tester, give Robin Instruments a call. I know they were taken over by Fluke, so you may have to search around. I believe that Robin can be contacted via http://www.robinelectronics.com. Generally, instruction books for testers won’t give acceptable values for EFLI.

The PAT Testing guide you have is not really good enough for this stuff as you are confirming that the appliance is safe (I am sure you know this. Please forgive me if I’m teaching you to suck eggs!). The objective after doing insulation tests is then to carry out an EFLI test. The PAT guide typically discusses bonding resistance values for appliances (also important) & yes, I do use a PAT tester for confirming this after I carry out a repair as well as carrying out an EFLI test either at the outlet or in the case of a cooker or oven at the terminals.

The Wiring Regs book is the only way to get the values you need. The other way (which is the method I sometimes use) is to use a program like Amtech Power software (I also do electrical installation work) which lists the common protective devices (MCBs) & the max EFLI vs. disconnection time. May be you have a friendly electrician who properly understands this stuff that can also help.

After a while, you will get a ‘feel’ for the correct values. But sometimes the value can be too low – this then can cause an issue with the MCB or fuse for other reasons.

Don’t let this scare you – it is always daunting in the beginning. No, gain without pain (or headache) 😆

If you want to learn about testing & how to interpret these values, may I suggest that you contact the local Tech College as these places often run courses on 16th Edition Inspection & Testing.

Let me know if you need further help – I’ll be pleased to help a fellow techie- just send another message on the forum or via e-mail on UKW & I’ll give you my personal e-mail address.

Regards

Michael

[sumphose]

Re: Earth Loop Impedence Test Equipment

A Pat test is only compulsary for those of us, that repair, any appliance, in non-domestic situations. This includes appliances repaired in our workshops.
😥

[Dave_Conway]

Re: Earth Loop Impedence Test Equipment

This seems to keep getting forgotten about so let’s get some definite figures, for now anyway.

Can anyone who wants a KMP4116 at £165 or a KMP4120 at £299/£309 please email me directly at dave_conway@btconnect.com and I’ll collate the quantities and sort it out from there for everyone.

Dave.

[washerdoctor]

Just a note on calibration,

In a previous firm, we ordered 2 pat testers, and for some reason were obliged to have them calibrated, despite being new. This also delayed delivery to us as the supplier sent them to a calibration company after they had received them from the manufacturer. I recall a hefty extra charge for this. We received the testers and 2 certificates of calibration eventually.

Anyway, When we came to use them, one worked fine, the other always showed a fault regardless.

We sent the faulty one back and the manufacturer told us that the wrong resistor had been fitted at the factory, so obviously it was wildly out of calibration

So my question is, what did the calibration company do for the £65 (I think) charge?

Obviously just slapped a sticker on the unit and printed a certificate. Thats good money isn’t it!

[Dave_Conway]

washerdoctor wrote:
So my question is, what did the calibration company do for the £65 (I think) charge?

Not a lot by the sound of it, TBH I have often wondered about the validity of calibration, considering if you drop the damn thing, which we have all done, any calibration test would be a waste of the expensive piece of A4 it is printed on 😯

But, safety test equipment does of course have to achieve a certain level of accuracy otherwise what is the point of using it.

Dave.

[lotusray]

Re: Earth Loop Impedence Test Equipment

dont know if this is still relevent but my mate is a manager in newey and eyre if a decent quantity is required can ask him for adecent discount
let me know some numbers see what he can do

[simonb]

Re: Earth Loop Impedence Test Equipment

just chipping in was looking through a list of testers from martindale they have a new socket tester(plug in) like the usual 3 lights but with a built in earth loop test(soft test no trip rcd) will fault path and with yes or no.

seems like a good compromise as i know of a lot of engineers who dont do earth loop test just plug and go.

on the subject does it really matter what the insulation reading is on appliance as long as theres a good earth 0.1 ohms i mean if its very low lets say 250k ie quarter of meg you know the things gona go bang soon. the legal requirement is 1 meg so what if its 1 meg now you pass it in few months its going to be below that anyway, on some machines with computer control/electronic switching is by triac so you dont get a reading from plug to componant(this is not covered by iee, not what iv read anyway) sometimes you get through on the neutral if switching is on live.
although if machine is next to sink i always check to see if sink is a same potential as appliance earth!

funny thing when i started at merloni a asked an engineer who had worked there from 20 years did he use a mega his reply was whats that a new thing they have brought out? im not to sure if he was on a wind up?all engineers at the time did not use one in my area and were not using one only when they bought big share of gda did they began to get issued with one.

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