loop impedance tester

jonny705 · Mar 31, 2015

Another question - :smile5:

When did the use of loop impedance testers first come about?

I tried to google it , but cannot find a definite answer, came up with an LCR meter though?

So how would you know the Ze before they came freely available and I guess affordable - just by enquiry at supplier?

And therefore would you have just used a resistance meter to calculate Zs, and when did/ would they have been used within the industry- i.e. how long ago ?

Also I/R testers , when were they first introduced / mandatory?

My friend gave me a yellow Robin analogue tester years ago when he used it for fixing white goods,

but that was age ago!

Deleted member 72666 · Mar 31, 2015

How old do you think we are?

Bobster · Mar 31, 2015

A 60w lamp and two lengths of wire

davesparks · Mar 31, 2015

Earliest reference I have to a loop impedance test is in a book from the 1950s
Earliest reference I have to an IR test is a book from 1939.
Occasionally you see wooden cased loop impedance testers made by clare on eBay,

7029 dave · Mar 31, 2015

I remember using the wooden boxed loop tester.

Deleted member 72666 · Mar 31, 2015

These testers have been around for a long time, when I first started out I was introduced to a wind up megger, the faster you wound it the more dc volts you got out, we used to easily get 750 volts! A favourite trick was to charge up a metal bodied condenser (the ones fitted across the contact points in a car distributor) and then you'd chuck it to some unsuspecting victim who'd then catch it, this always resulted in a 'small' electric shock as the fly lead would whack the back of the hand, happy days! As for the loop testers I remember we were given digital versions of them when the 15th edition was introduced in the early eighties.

Dcf · Mar 31, 2015

Rob said:
A 60w lamp and two lengths of wire

Add a bell and battery set to that.
although I used to have a 15w Pygmy lamp in mine.
loop testers were around in the 80s....the firm I did my time with had one between 14 Sparks and 7 laddies!
it used to come up with an overheat when it did too many tests which wasn't many tbh

Marvo · Mar 31, 2015

I think they used to be called 'earth ohmmeters' in the early days.

Knobhead · Apr 1, 2015

As an apprentice the only thing we used was a Ductor for dead tests. If you consider each plants N→E link was connected direct to the plant MET, it wasn’t a big issue.

I have used RoB’s lamp method more than once.