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Re: Does anyone use this loop tester info required
madangler1
For the purposes of technical debate lets just carry this forward. Whilst I agree that no-trip loop testers can sometimes be problematic with consisent readings, I think that you would agree that taking an EFLI reading will be a good indicator as to whether or not the circuit will disconnect under fault.
Even a conventional loop tester can give erronous readings especially if the house is extremely close to the transformer (high PFCs, reading errors due to inductive reactance etc). It is known fact that at loop impedance values accuracy (not resolution) can be as poor as 30{e5d1b7155a01ef1f3b9c9968eaba33524ee81600d00d4be2b4d93ac2e58cec2d}.
In jest, the only sane test is to drop a big spanner across the terminals & if the CPD activates, all is good 😈 :rotfl:
Lets examine your statement that 100 or 200 ohms is good enough. What does this mean in reality? This may be true / acceptable for 30mA RCD (additionally) protected circuits.
For non-RCD protected circuits (of which there are still many in existance) The protective device may not disconnect under fault especially if there is no RCD. The outcome could be fire or elevated touch voltages leading to shock risk.
I think as appliance engineers, there must be awareness of acceptable values – be risk adverse. Don’t take a chance.
Regards
Re: Does anyone use this loop tester info required
at 2nd para add in ….low loop impedance values accuracy…..etc
Thinking faster than typing …..
Re: Does anyone use this loop tester info required
I wonder if my central heating engineer carries out these tests when he services my boiler?
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http://www.kitchenkitsw.comRe: Does anyone use this loop tester info required
i agree with everything you say, in fact i argued as much when i had my manufacture training years ago having just quit sparking but i learnt in reality having engineers try and figure out what system the customer is on is never going to happen, there has to be a line in the sand somewhere, Indesit and British Gas set it at 200ohm based on the fact in the majority of cases this is adequate to allow safe disconnect regardless of the system and if its in the regulation specified times or not.
This may not be 100{e5d1b7155a01ef1f3b9c9968eaba33524ee81600d00d4be2b4d93ac2e58cec2d} but from out point of view its enough.
Simply an engineer needs to know the socket is wired correctly, its earthed and there is a reasonable chance that in a fault condition the protecting device will work.
Re: Does anyone use this loop tester info required
200 Ohm is way too high. It would result in an earth fault current of just over 1 amp, not enough to blow any fuse or circuit breaker. Granted, with a working RCD, you would be OK. Otherwise, you may as well not bother to do the test at all.
If Indesit and British Gas really are advocating a blanket pass level of 200 Ohm, that is truly shocking. It could give a false sense of security and sooner or later result in an engineer being electrocuted.
Re: Does anyone use this loop tester info required
Thank you for agreeing with me Stratford Girl.
When I read that these commercial organisations were allegedly promoting this practice, it did raise concerns.
If appliance ‘engineers’ cannot recognise the difference between TN & TT installations and cannot interpret loop impedance readings then I, for one, do wonder about the training for the individuals dealing with electrical appliances.
I am sure that someone will say that the concerns are unfounded as there are minimal incidents reported. Just wait until an MP’s relative is killed or injured. Everything will change. Much tighter regulation will then come in. Surely, as an industry, education and training must improve.
Regards
Re: Does anyone use this loop tester info required
Brains wrote:Thank you for agreeing with me Stratford Girl.
When I read that these commercial organisations were allegedly promoting this practice, it did raise concerns.
If appliance ‘engineers’ cannot recognise the difference between TN & TT installations and cannot interpret loop impedance readings then I, for one, do wonder about the training for the individuals dealing with electrical appliances.
I am sure that someone will say that the concerns are unfounded as there are minimal incidents reported. Just wait until an MP’s relative is killed or injured. Everything will change. Much tighter regulation will then come in. Surely, as an industry, education and training must improve.
Regards
Just a note, having not worked for Indesit for a few years i have made a call and they now state that below 2 is acceptable regardless of the system and 3 to 200 is acceptable IF an RCD is fitted.
i did get that wrong.
i do agree it does make you wonder at times, but iv seen it in every industry iv been in people who are performing tests and repaired with no underlying background to how it works take Gas, i had my meter changed last year, a guy turned up in a ford fiesta wearing jeans and t shirt roughly 19 years old, walks in with a spanner and the meter, spends 5 minutes swapping it over, popped back to the car for the u gauge and did the test, i asked him a few questions and he had just got the job never working with gas before, had a 1 week coarse and that was it :eeek:as its the utility side no gas safe was required.
Re: Does anyone use this loop tester info required
Having worked in a few EU countries for a German Brand, they do not equip there Appliance engineers with Loop testers, mega’s etc etc.
The only time an Insulation tester arrived in the Service Dept was due to earth fault on a batch of induction hobs, it was returned to H/O a few weeks after arrival.
Gotta luv EU regulations.
The test we carry out are still only good for the time there done and unlike a spark who is regulated there is no proof you actually did the test.
Its surprising how many engineers records I see where they still earth test and record readings for double insulated cooker hoods.
Like I stated before you wouldn’t want to go to your GP for a minor pain and end up in hospital for a week doing needless tests just in case.
The HSE did a survey between 1996/7-2002/3 of all fatal, major and over 3-day injury accidents occurring in all industries as
reported via RIDDOR.1,102,269 total accidents, only 1{e5d1b7155a01ef1f3b9c9968eaba33524ee81600d00d4be2b4d93ac2e58cec2d} involved Electricity and 6{e5d1b7155a01ef1f3b9c9968eaba33524ee81600d00d4be2b4d93ac2e58cec2d} electricity was involved. Our industry there was 3 incidents.
7 yrs that includes, ship building, heavy industry, construction etc etc etc. More people got hurt by there tool boxes and spanners than by an electric shock. :rotfl:
Not only will we soon need to wear a hard hat, high vis vest, rubber boots, gloves, plus a safety case in neon colours for our tools, we’ll need also the same for our laptops.
Mrs Smith will drop dead with laughter when she opens the door to us.
Re: Does anyone use this loop tester info required
The engineer would only get electrocuted if he had left the appliance badly repaired and with no earth, and if he was that bad he wouldnt be able to carry out these tests. I only know of one instance of an engineer being electrocuted and that was in leicester some 25 years ago at AA vacuums when an engineer put his had in the drum to spin it as the customer said it was noisy and got electrocuted as the previous engineer left the earth off.
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http://www.kitchenkitsw.comRe: Does anyone use this loop tester info required
Thanks for the up to date information re Indesit, madangler1. The two level approach of 2 ohm maximum earth fault loop impedance where not protected by an RCD and 200 ohm with RCD protection may be a sensible rule of thumb as a basic safety check for service engineers.
Re: Does anyone use this loop tester info required
At long last common sense prevails.
Thank you for getting back to us Madangler1. 😀
Regards
Re: Does anyone use this loop tester info required
Common sense went out the window when people started believing everything there told as opposed to logical thinking, then again judging by some of the things I see daily its the safe option.
Its a big world out there, sometimes only the easily manipulated are targeted, and Brits I’m afraid are easily manipulated, I believe its been re branded in many guises one is “Being professional” etc etc.
How many calls do people on here get from PAT companies referring appliances such as D/W etc etc in office kitchens with Earth Faults 😉
I’ve never had any.
Re: Does anyone use this loop tester info required
lee8 wrote:
How many calls do people on here get from PAT companies referring appliances such as D/W etc etc in office kitchens with Earth Faults 😉I’ve never had any.
Probably in that environment anything faulty just gets automatically chucked.
Slightly off-topic, I went into a public library once, when on a camping holiday, and asked if I could use an electrical socket to charge up my camcorder battery whilst I used a computer. Librarian looked at scruffy old me and said, “I’m afraid we couldn’t risk plugging in anything which hasn’t been safety tested.”
Mike.
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