Who does just a Zs when carrying out a periodic on a lighting circuit

[ezzzekiel]

short answer yes but only if it suited the powers to be where blame needed to be laid, otherwise no one gives a stuff.

 

[nickblake]

We are trained electricians electricity is our life , i just want to grab hold of the spec wearing pen pushing person that says you cant do this live oh for gods sake , like a driving schoolyour driving lesson you cant start the car up or move it just in case you crash , there are more people injured in cars so when are they going to ban them , you always treat circuits as if they were live even when you know they are dead then there is not a problem , yes maybee for a trainee who's never carried out electrical work then fair enough thats why there is training , how many places have banned step ladders , they are very safe if used correctly if not you fall off , and working plat forms arnt the be all and end all i had 6 cable clips to put in i worked off a platform fell and ended up in casualty ,slipped off a step silly thing to do if i was using stemps it wouldnt have happend sorry for going off on one just get so dam frustrated !!!!

 

[Deleted member 26818]

I must admit, it often makes me chuckle when sitting in on site inductions we are told to treat all cables as live, and not to touch them or we'll be chucked off site.

 

[telectrix]

We are trained electricians electricity is our life , i just want to grab hold of the spec wearing pen pushing person that says you cant do this live oh for gods sake , like a driving schoolyour driving lesson you cant start the car up or move it just in case you crash , there are more people injured in cars so when are they going to ban them , you always treat circuits as if they were live even when you know they are dead then there is not a problem , yes maybee for a trainee who's never carried out electrical work then fair enough thats why there is training , how many places have banned step ladders , they are very safe if used correctly if not you fall off , and working plat forms arnt the be all and end all i had 6 cable clips to put in i worked off a platform fell and ended up in casualty ,slipped off a step silly thing to do if i was using stemps it wouldnt have happend sorry for going off on one just get so dam frustrated !!!!

agree 100%, nick. whilst safe working practice is essential, if the red tape and nonsense were to be cut and more common sense applied, the only down side would be more "suits" on the dole.

 

[nickblake]

I must admit, it often makes me chuckle when sitting in on site inductions we are told to treat all cables as live, and not to touch them or we'll be chucked off site.

Sat through a site induction even though i had my CSCS card wouldnt let me on site otherwise ,went through the whole safety manual well it felt like it 11/2 hours of it , all i had to do was reset an MCB , funniest thing was it was in the office the site induction took place !!!

Tel now that would be a shame lol but what i will say i think it may well back fire because youngsters will not see the dangers , and will probably end up getting injured by the thing they are least lickly to get injured by , dont get me wrong im all for Health and safety it saves lives but feel its over the top

 

[Hawca]

In short, to the first part, you can calculate Zs, how ever never can you calculate Ze or R1+R2.

reasoning behind this is Zs only tells us an earth fault path nothing more.

Ze tells us we have an acceptable earth (not a path through the bonding etc)
R1and R2 tells us we have a physical return path via CPC (Not through parallel paths etc)

Never calculate R1+R2 or Ze

the whole working live thing..

it is unreasonable in ALL the circumstances for it to be made dead; this bit here tells us we can work live when testing... as pointed out we have to carry out Ze and Zs testing along with RCD and Ipf. we cannot and never will be able to test the when dead, and therefore have to test live.

 

[Deleted member 26818]

We don't have to test Ze or PFC as they can be determined by enquiry.
Zs can be calculated using the measured R1 + R2 value added to the enquired Ze value.
That just leaves the RCD test.

 

[IQ Electrical]

We don't have to test Ze or PFC as they can be determined by enquiry.
Zs can be calculated using the measured R1 + R2 value added to the enquired Ze value.
That just leaves the RCD test.

Yes, Spin's absolutely correct, the above are all accepted ways of deriving the figures to fill in the form, but not one of MY forms, my values are measured and confirmation of an adequate means of earthing etc. is obtained.

I guarantee that I can take a better guess at Ze and then PFC figures than any chap at the DNO can give me!

 

[malcolmsanford]

Agree with both the Spin and the IQ, though mostly an enquired Ze would only really be seeked at a designed stage, though in some cases I have known Ze obtained by enquiry on a large industrial complex where gaining access to take a measurement was virtually impossible during a PIR as it would mean closing down the entire complex. Not ideal but it is there for such occasions

 

[Sparky Ninja]

I guarantee that I can take a better guess at Ze and then PFC figures than any chap at the DNO can give me!

That's because you can bother turning up.

 

[Hawca]

We don't have to test Ze or PFC as they can be determined by enquiry.
Zs can be calculated using the measured R1 + R2 value added to the enquired Ze value.
That just leaves the RCD test.

this is fine in theory, and thats where it should stay, in design or at college.

Ze by enquiry does not nor will it ever prove beyond any doubt that an installation has a physical earth coming into the installation. the point of the PIR is to see if an installation is safe or fit for use. how can we make a judgement on this if we do not know if an earth comes into the installation?

therefore we have to test Ze, and in order to do so we have to work live.

 

[beaver74]

I have come across a water heater that had a vary healthy Zs which was taken from the water pipe .now if the pipe had been plastic there goes your earth.it is for this reason R1+R2 should be taken to prove an electrical earth