testing L/N to earth

KNIPEX · Nov 21, 2008

hi Quick question as the regs say when you cant remove lamps electronic equipment its ok to do

line/neutral together to earth

how does this bypass all the electronics im very curious how it works.

as ive you did live/neutral together would show a short.

also if you do the above, do u still have to test, neutral to earth

and line to earth??

as you have done them above.

also could you leave computers on and other stuff plugged in and do i/r this way or would it still blow them

thanks for your help.

jeremy · Nov 22, 2008

I'm a bit pi55ed so this might not come out as planned!!If P and N are at the same potential, be it 5, 25 50 or 500 volts as there is no voltage slope for them to slide down then their relationship with "earth" can be measured as if one. If the reading from both is measured to be within limits then the reading from either ONE would also be ok. I'm pretty sure that's right!!

beaver74 · Nov 23, 2008

the way i look at it is:
if you are meggering L/N connected together to earth all loads conected to circuit can not be damaged as 500v is between L/N to earth

WarrenG · Nov 23, 2008

More of this on this thread here:

http://www.electriciansforums.net/general-electrical-discussion/2904-zs.html

Warren

uksel · Nov 23, 2008

took the link right out of my mouth warrenG

i'd always tested seperately and never considered having to IR P/N>E but the thread warren has linked to pretty much mimics this question

coxy · Nov 24, 2008

Hi,
When doing periodic testing sometimes it is not possible to disconnect all lamps etc.Perfectly ok to test line & neutral together to earth,and make sure you put down limitations on certs.

randyrat · Dec 8, 2008

Back to school chaps....
The electric wiggle goes up from the live, through the "thing" then back down the neutral. It does this because there is a "potential difference" between L and N. If you link the live and neutral at the CU, then any electric wiggle you try and push up the cable will go nowhere, as there is no Potential difference between them. Therefore no current flow through the "thing" So its not going to be damaged, right!!!
Easy innit?

Spudnik · Dec 8, 2008

randyrat said:
Back to school chaps....
The electric wiggle goes up from the live, through the "thing" then back down the neutral. It does this because there is a "potential difference" between L and N. If you link the live and neutral at the CU, then any electric wiggle you try and push up the cable will go nowhere, as there is no Potential difference between them. Therefore no current flow through the "thing" So its not going to be damaged, right!!!
Easy innit?

Fantastic explanation!