Testing A Generator

[fulham sparks]

Have to test a 1 x 500kVA Generator and need to get a zs and ze at the generator... Will they be the same thing as that is the start and end point of my test? Its been a long day so need your help :s cheers!

 

[Manator]

They will not be the same test. You have to remember that Ze will be tested with any bonding removed, Zs will be with all bonding in place. The readings may indeed be very similar but you should always remember the basic principles of each test.

 

[fulham sparks]

Hi mate.. I understand this but all i am testing is the generator nothing after this.. What bonding will there be? Just need to test the rcd , zs and ze... Bit baffled

 

[steptoe]

would the genny not be TT ?

is this a standby genny or a back-up?

 

[SLIPSHOD & SLAPDASH]

I have a similar job next week thats going to be different to my normal stuff. Have to wire up a generator for a compound in a closed road for a utilities company. There's a portacabin, floodlights and hoarding lights. There's no way i am going to hammer an earth rod into the tarmac or pavement. Any ideas other than hope the groundworks guys have a Cat scanner .

 

[fulham sparks]

This will be running constant and it should be a tt but will find out tomorrow.. Can the earth be connected to the buildings earth bar? Im really just guessing what the job is going to look like tomorrow

 

[steptoe]

if its a standalone genny I would say no, it needs to be TT,

if it is TT then you need to do an Ra test, NOT Ze,

and Ra and Zs are 2 entirely different tests,

 

[SLIPSHOD & SLAPDASH]

But you can do  'Test method 2' test which is the same as a Ze 

 

[steptoe]

you can, but its still not as good as, or accurate, IMHO,

I dont see the point, its just as easy to do it properly, ok, so a bit more time, but at least you know the results are right, and its easy to sleep at night.

 

[fulham sparks]

Test 2? Cant remember lol

 

[steptoe]

basically a Ze on a rod,

but no-body ever method2's a ring anymore, so why method2 a rod?

just do it the preferred method,

EDIT

are we even allowed to method2 a ring these days?  :C

 

[fulham sparks]

Sweet! That sounds like the easiest option if it is a tt!

 

[steptoe]

so, a Ze would be the rod disconnected, and a Zs would be the rod connected to the genny,

BTW, I still dont think its a proper test for a TT system,  :|

 

[SLIPSHOD & SLAPDASH]

Me !

basically a Ze on a rod,

but no-body ever method2's a ring anymore, so why method2 a rod?

just do it the preferred method,

EDIT

are we even allowed to method2 a ring these days?  :C ,

I have not done a TT for  3 years and about 6 years before that. I don't have a   earth electrode (3 wire) tester anymore as my retired partner had it away so next week i will be using method 2 which is still in the latest GN3. Thats if you will come round and hammer a rod into a public road for me.

 

[fulham sparks]

Sweet! That sounds like the easiest option if it is a tt!

 

[steptoe]

Me !

I have not done a TT for  3 years and about 6 years before that. I don't have a   earth electrode (3 wire) tester anymore as my retired partner had it away so next week i will be using method 2 which is still in the latest GN3. Thats if you will come round and hammer a rod into a public road for me.

do you want a quote?

and,

NO,

I wont do it for 2 boxes of beer and a bottle of buckfast! 

what you want is a sledge with a fibreglass shaft and a flashmask, 

do you want me to bang 5 in so we can Ra it too? 

 

[kme]

Erm........

How the heck does anyone think they can do a method 2 loop test on a TT gennie!!! Try drawing the path - you haven`t got a remote star point.

An earth rod tester is the ONLY option for the Ra I`m afraid.

O/P - what Zs are you testing?

 

[steptoe]

Erm........

How the heck does anyone think they can do a method 2 loop test on a TT gennie!!! Try drawing the path - you haven`t got a remote star point.

An earth rod tester is the ONLY option for the Ra I`m afraid.

O/P - what Zs are you testing?

good point,

not enough Guinness   for me to think straight maybe tonight,  :slap

SLIPS,

you still wanting that quote? 

 

[Chr!s]

Kme

If we have a three phase gennie how do we tie the voltage down?

Where would we connect the protective earth, now draw out the path.

Do you think a 500kva can be floating?

Regards

 

[steptoe]

Kme

If we have a three phase gennie how do we tie the voltage down?

Where would we connect the protective earth, now draw out the path.

Do you think a 500kva can be floating?

Regards

but,

you have to disconnect it to do a Zs,