No live testing except where it's a must

[trev]

I agree with all of you but the local college doesn't advise live testing of Zs

So what about Ze, PEFC,PSCC? Or are those live tests acceptable? I've probably never heard such nonsense. Rather than discouraging these tests they should be teaching students how to carry them out safely and properly.

 

[Les Macaulay]

Adam, that's all very well but I was told of a factory inspector or similar reported a spark who was working in a warehouse that had been flooded and left the app standing by at the main dist board as a "safe Isolation". Again if these guys did appear on site you cannot assume you know better even if you think you do. I feel the same as you but have to respect the bofins.

 

[moose]

Calcs are ok in some cases maybe a percentage to help speed you up in this get it done world we live in, but not for all the test sheet the calc for a ring main is not the same as Zs=Ze+(R1+R2), Can you Tell what it is yet

 

[Les Macaulay]

It's because there is no option other than live testing. A socket is ok as the test lead is designed to be safely plugged in, they say. I'm not arguing against live testing, simply stating what is recommended by trainers on the Inspection Courses.
We were made to wear gogles while doing the live Ze test and comply with the rule earth, neutral then line order of probing and the reverse when finished the test.

 

[Les Macaulay]

sockets are tested live

 

[Sintra]

I agree with all of you but the local college doesn't advise live testing of Zs, just as Markc123 said above. Is there not a call for say BC adapter leads and small and large and giant ES adapter leads for loop testers? So no H & S inspector walking in on me probing behind a FCU for a Zs reading would be critical? Same at any other live terminals, except at the incoming supply with the main earthing lead disconnected and the CU main switch open?

Well ask your college how they can determine 100% that disconnection times will be met. Say you are testing final circuits from a BMS are you saying that calculation will give you the Zs from your R1+R2 and your Zdb.

 

[trev]

The trainers are idiots. the rule of earth neutral then line and the reverse is common sense though.
Now and again you may come across a situation where you may have no other option but to work live, a lot of guys on here will have been in that situation. Apparently we're not allowed to even consider doing that now.

 

[markc123]

I agree with Trev and the gang that it's complete nonsense. However, on my travels from what i hear i do think that what Les is saying is correct (no matter if we all disagree with it) - they are discouraging live testing as much as possible now a days, thus all the apprentices are getting told and brought up as if its incredibly dangerous when they should be shown how to live test safely IMO.

 

[Adam W]

Adam, that's all very well but I was told of a factory inspector or similar reported a spark who was working in a warehouse that had been flooded and left the app standing by at the main dist board as a "safe Isolation". Again if these guys did appear on site you cannot assume you know better even if you think you do. I feel the same as you but have to respect the bofins.

In that situation I would argue that if it's so dangerous to test Zs then there's no way you should be testing Ze. If there's no better way to safely isolate and lock off, leaving a suitable sentry by the switch is acceptable IMO.
When I did my 2391 we measured Zs on all the circuits except a 3 phase socket, which would involve dismantling it to expose live parts with a 400v potential between phases. I would argue with the H&S jobsworth that while he might not be a skilled person and thereby competent to test live, I am.

 

[Les Macaulay]

Again, Markc123 is reading from the same song sheet as I. There is no doubt that live testing is the only true reading you will get but if R1 +R2 measured dead then added to Zs, is within the limits imposed for disconnection times then I think that everyone will accept the reading attained this way.
Thanks everyone

 

[moose]

Lol another note failed many by calc but when tested its always lower, Money making skeem in the making, Max Ze in TN-s in regs not measured and then Dead test R1+R2 you try...much bigger usually

 

[Engineer54]

Where in god's name, do these collage lecturers come from these days?? If they aren't instilling personal scaremongering into students on exporting PME and not to use the armour of a SWA cable as the CPC, they're teaching crap like this!!

 

[Rampantchilli]

my employers will NOT accept calculated readings where live testing can be done, however they do have strict safe working procedures, including safe isolation and locking off, even if your the only person present.

i thought test leads ARE considered safe to work live because of the 2mm exposed end, and the slip barriers they have.

the earth neutral line procedure was taught to me back in the 80's, very safe procedure to adopt

 

[telectrix]

next we'll have gas safe recommending tgesting for a gas leak with the main gas tap off.

 

[SPARTYKUS]

My company ONLY allows live testing for Zs.

we're international, Paris,Rome, Wolverhampton. at least 3000 employees.


(just me)