110v earth loop impedance

[matdom]

My test meter only works on 230v....

So... Is there a way of working out the Earth fault loop impedance on a 110v supply that is supplied by a hardwired 110v Centre tapped to earth transformer?

Anyone else come across this.

I have some additional 110v sockets to fit in a workshop but need to get this figured out for Minor works cert.

Any help would be appreciated.

Cheers

 

[Bobster]

Your going to need to borrow another test meter if you want to measure the Zs. If not you'll have to just calculate it in the same way as normal.

Remember the maximum permitted Zs for MCBs @55v is significantly less than @230V

 

[matdom]

Been looking on the net for info on this and it doesn't appear it's that straight forward, not saying you're wrong obviously.

it's not on MCB it's got 88's in the board.

 

[tony mc]

What about table 41.6 have you looked there ?

 

[Farmelectrics]

that tells you your max values

 

[Farmelectrics]

think the op is asking how he tests it with out the right meter or calculates it

 

[matdom]

yeah, I know what the MAX is, I just need to find a way to get a reading without a meter, But looking on the net, it seems a bit of an oddball, I found one post that says it doesn't even need testing because technically there isn't a real protective earth as it will constantly sit at 55v anyway???

just a bit stuck with it really!

the only thing I can think of its doing 2 readings, one for supply (Primary side of tran) and then a second for the output side (Secondary winding on transformer)

 

[Bobster]

Zs = Ze + (R1+R2)

The earth most certainly doesn't 'hang at 55v' the two line conductors are at 55v in reference to the cpc.

 

[matdom]

I was just trying to find a bit of clarity on it because the more I thought about it the more I confused myself......but some of the crap written on the net is worrying.

 

[Brightspark2]

I was just trying to find a bit of clarity on it because the more I thought about it the more I confused myself......but some of the crap written on the net is worrying.

Most of it on here!!... Wahey...

 

[D Skelton]

Measure R1+R2 at each point of the 110V circuit through each side of the windings, a DEAD TEST that is (just thought I'd throw that in for clarity), and record the highest value. Divide this value by the expected power factor of the 110V system and there's your earth fault loop impedance value. When working out earth fault loop impedance on the secondary side, the primary side doesn't even come into it.