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Re: meggers
adv wrote:mmmm how much for one o them? 😆
Says £39 exc. VAT on the web-site. http://www.kewtechcorp.com/products/pat/patadapter1.htm
You might get it bit cheaper through WF or Edmundsons etc
The MFTs are bit more, starting from about £500 exc. VAT
🙂Non-contact tester e.g Megger VF2 about £15 exc. VAT
Re: meggers
leavemetogetonwithit wrote:I’m not sure I should tell this little tale here but I’ve been saving it up for a few years now and I ought to tell it before I forget. As if I could.
I was called to an AEG wm which wasn’t starting up. In my carefree way (as was) I took the lid off, switched on and started poking around with my LED screwdriver (one hand in my pocket 😉 ). To my confusion I found there was live potential present on all the exposed metal!
I turned off the power and opened up the plug. The earth wire was wired to the live terminal and the live wire to the earth 😯 .
I informed the customer of the situation.
Turned out the customer had just moved into the house and the moving company had got one of their guys to remove and rewire the plug as it had to go through a hole in the worktop. I asked him for the name of the company so I could contact them and advise them not to leave such work to unqualified operatives. They said they didn’t have the name to hand. So I asked them to find out and call me on the morrow. Not sure, maybe the customer had done it himself and was trying to cover up. Anyway, they never called me.
Make of that what you will.
Mike.Lucky escape – could have been horrible 😯 . I also use a non-contact tester – whilst not fool-proof it has saved me a few times.
Re: meggers
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I can see now that I’m gonna’ have to think seriously about getting a new pannier rack for the front of my bike to carry the two extra tools that I don’t currently (no pun intended) have, i.e. loop tester and PAT tester. Maybe I will get a bike trailer a bit like one of them wheeled suitcases that I can just unhook and wheel to the door.Very Wallace & Grommitt 🙂
Now wouldn’t it be brilliant if someone would come up with a way to make a meter that would perform ALL these testing tasks so we could breeze in and get the job done without tripping over all the various leads trailing about before we even get started on changing that door seal.
Or maybe somebody already has?
Mike.
Mike you can do a limited amount of appliance testing with a MultiFunction Tester that does insulation, continuity & loop. There is an adaptor made that will allow the use of an MFT to test appliances.Take a look at this link:
http://www.kewtechcorp.com/products/pat/patadapter1.htm
I have not yet had the opportunity to use one of these, so I don’t know how well it works.
Hope this helps lighten the load on the pannier 😉
Regards
Re: meggers
Some loop testers do have an ‘accessory’ lead for testing appliance earthing. However, I would suggest for washing machines, tumble dryers etc (e.g anything withing a plug) use an appliance tester.
For a high current appliance such as a cooker, the use of a loop tester with an ‘accessory’ lead is not a bad idea.
Remember that you can verify loop Z at the cooker terminals. However, please work safe when undertaking live testing.
Regards
Re: meggers
Mike
Answering & responding to each point in turn:
1. Test earth continuity within appliance with a multimeter. That’s at 9 volts, mark you.
This gives an indication but will not pick up broken or strained conductors – thats why an Appliance Tester uses high current (nominally 20A).
2. Test insulation resistance at 500v.
Yep. thats okay. Although there is a move to measure earth leakage current as an alternative means of assessing insulation resistance (another subject for another day).
3. Test earth loop impedance at socket with meter which measures earth effectiveness at some 20 amps using the household’s own supply.
What I don’t understand is this. We are not testing the appliance’s own earth path at 240v / 20 amps so what’s the point of testing the supply earth at that level? If the earth path in the appliance were to be insufficiently robust to not break down at 240v / 20 amps or less the fact of the supply earth being good enough would be irrelevant.
The normal method of EFLI testing employed by a loop tester is to compare unloaded loop circuit voltage with the circuit voltage when loaded with a low resistance typically 10-20 ohms. This is where the 20A comes in.
Keep in mind what I said before. Care must be taken when carrying out EFLI testing. This method of test can create a shock hazard if the line-earth loop impedance is high & the test duration is not limited by the test instrument. In theses circumstances the potential of the the protectective (earth) conductor could approach line voltage for the duration of the test (hence my comment about testers indicating high PE voltages). Also stresses the need for Main Bonding Conductors within the installation.
OK, it’s a very unlikely scenario but isn’t that what testing should be covering?
Mike.
I hope I have helped your understanding with this. Please let me know if I need to provide some more information.Regards
Re: meggers
Quote ”Oh Mike, you don’t have to that all if you do not wish, it’s not obligitory. But a Martingdale type mains continuity tester will suffice as a quick and effective means of testing the appliance’s supply line if you wish. They are cheap to buy and very effective”. Unquote.
Martin & MikeWithout wishing to get in the middle of your discussion, please, please be careful when using Martindale type plug-in testers. The neons will light at a very low voltage level. Great for a sanity check. Useless for checking reversed neutral-earth connections. Useless for confirming a good earth.
Please don’t take this the wrong way – but just a small reminder of why an EFLI tester should be used. Keep in mind that by measuring EFLI, you are confirming that the impedance is low enough for the circuit-protective- device (CPD) to trip within a specified period of time under fault. Keep in mind that high EFLI values may cause CPDs not to trip or take a long time to trip.
Most good EFLI Testers will indicate reversed/ incorrect polarity. Some will indicated high protective-earth voltages and abort the EFLI test.
Hope this helps.
Regards
Re: meggers
Sorry Martin
Don’t want to put anyone off testing.
Just wanted to remind everyone of the variables.
May I also suggest our colleagues to inspect the method of earthing and circuit protection first prior to testing.
Reasons: First to ensure that there is a Main Earth Connection. In a lot of older properties it is not uncommon to identify no Main Earth or ‘Water-Pipe’ earths (not Main Protective Bonding – another subject for another day?). This is to prevent inadvertent /elevated shock risks to people within the property.
Also, to prevent inadvertent tripping of RCDs – annoying to the customer if they are using a PC elsewhere in the house and if they do not know how to reset timeswitches.
I would also suggest that you inform the customer prior to carrying out these measurement.
If you want me to contribute further techno-babble let me know & I would be happy to do so. 😉
Regards
Re: meggers
Martin
The EFLI data you have supplied refers to a TN systems (i.e TN-S or TN-C-S). You need to take into account TT systems that use earth-rods. Also, if there is an 30mA RCD providing additional protection then max allowable EFLI can go up to 1667 ohms.
I would like to suggest that if EFLI testig is carried out then, the RCD trip times should be verified. I know that this is extra work, but, is a key part of safety testing and takes just a few minutes with an appropriate tester.
Also, with an installation that is RCD protected, checking Fault Loop Impedance from L-N (ZL-N) will provide a good ‘sanity check’ to ensure MCB disconnection within the required time for line to neutral fault.
Hope this helps
Regards
Re: Creda Cooker Model Collection C366E
Phidom
Hmmm………. I was wondering if it was a burnt-out neutral. I do have all the required test gear – Megger, Loop tester etc.
On the other-hand, if the oven control was in the ‘off’ position, can’t see how it work unless the controller had failed shorted? Any thoughts?
Regards
Re: De Dietrich Range Cooker CX4844U1
Thanks Steve
As been said many times by others, Connect is the last resort. Would you have the manufacturer part no. ? Hopefully, then my element supplier can sort out something more reasonable.
Thanks
Regards
Re: Bosch Dishwasher SMS44542GB/14
Chris
Well, it was the fuse in the Switched FCU. Checked insulation values. Seems fine.
Ran the dishwasher while I was fixing an electric oven. Seems fine phoned today – they have used it a number of times – no problems.
Thanks for the suggestions.
Regards
