Low resistance fault replicated on a made up rig

[Paulconlon]

Possibly a daft one this lads but any insight welcome. Have set a dummy rig up at home and am trying to replicate a low resistance fault on a ring main. No prob getting off scale high and zero readings but anyone think of a way of creating a low but not zero reading.

 

[static zap]

Since it need to be resistance is there any possibility of circuit being energised
(Resistor will become an electric Fire -or- lightbulb ..(practical examples rather than) some fire risk !
Do you want poor IR type values ?

 

[James]

You could run a 100m reel of 1mm down the garden.
Join brown and blue at the far end.

200m of 1mm should have a resistance that is low but measurable.
Keep the current below 13A and not for long durations and all should be fine.

 

[SJD]

Depends what you call a low resistance, but as mentioned, a 230V lamp - e.g. halogen lamp (tens of Ohms, depending on rating), or a 230V neon (fraction of a MOhm).

Plus you don't say if this is between L & N, or between two different conductors such as a N to E low resistance?

 

[PEG]

A man after my own heart! Delete Facebook,and get experimenting in the garage

I will describe a method of inserting a fault test-bed,in to your rig,which i made many years back. All you need is a piece of board or plastic,1/2" thick,12" x 4" with two,fixed 3 terminal connectors or chocky blocks,one at each end.
This is inserted anywhere you like,in a ring or radial circuit,on your board.

Inbetween these two connectors,is your play area. I had several standard layouts,and will describe a couple.

One,was a 12" piece of T&E,with the middle 4",carefully stripped of sheathing and insulation,to reveal three,bare,conductors. These can have any number of materials laid across,or placed under,2 or 3 of them,and tested accordingly.

Damp or wet cavity insulation,plasterboard and brick,being favourites,but i never ran out of ideas....a handful of ashes,from any common building material,then dampen it....i even remember using dead mice...dry or fresh ...basically,it is an operation of deliberately using mediums you will encounter in real life,and practising with your test device,so the readings correlate to what you know,rather than what you are seeking,which invariably will be the case in the field.

The main thing you are aiming for,is NOT to be surprised,when testing on an actual installation,and getting confident,with your chosen test instruments.

There is no wrong material to introduce in to a circuit....nature and the great British public,will see to that...you can take that, from a man who,at the age of fifteen,woke one morning,desperate to see what the resistance was,of a single strand of galvanised,barbed wire,around a 4 acre field

 

[static zap]

single strand of galvanised,barbed wire,around a 4 acre field

I have 12 inches of green coated thin steel garden wire with (Coaxed-copper-wrapped-"soldered ends") .. for about 0.07 Ohms Hard wearing "standard"!

 

[DPG]

Low resistance high power resistors can be bought from RS, etc. Or Ebay if you want a better price! Obviously make sure the max working voltage is high enough.

 

[Paulconlon]

A man after my own heart! Delete Facebook,and get experimenting in the garage

I will describe a method of inserting a fault test-bed,in to your rig,which i made many years back. All you need is a piece of board or plastic,1/2" thick,12" x 4" with two,fixed 3 terminal connectors or chocky blocks,one at each end.
This is inserted anywhere you like,in a ring or radial circuit,on your board.

Inbetween these two connectors,is your play area. I had several standard layouts,and will describe a couple.

One,was a 12" piece of T&E,with the middle 4",carefully stripped of sheathing and insulation,to reveal three,bare,conductors. These can have any number of materials laid across,or placed under,2 or 3 of them,and tested accordingly.

Damp or wet cavity insulation,plasterboard and brick,being favourites,but i never ran out of ideas....a handful of ashes,from any common building material,then dampen it....i even remember using dead mice...dry or fresh ...basically,it is an operation of deliberately using mediums you will encounter in real life,and practising with your test device,so the readings correlate to what you know,rather than what you are seeking,which invariably will be the case in the field.

The main thing you are aiming for,is NOT to be surprised,when testing on an actual installation,and getting confident,with your chosen test instruments.

There is no wrong material to introduce in to a circuit....nature and the great British public,will see to that...you can take that, from a man who,at the age of fifteen,woke one morning,desperate to see what the resistance was,of a single strand of galvanised,barbed wire,around a 4 acre field

What a cracking reply that is. And much appreciated. Will be on the rig first thing tomorrow having a go at that. Can't see me getting any sleep tonight. Thanks again. Will get back to you with the readings.

 

[PEG]

I have 12 inches of green coated thin steel garden wire with (Coaxed-copper-wrapped-"soldered ends") .. for about 0.07 Ohms Hard wearing "standard"!

Hi,i can not remember exactly what the barbed wire reading was,,,maybe 10 Ohms,i do remember it being less than calculated,but the Buzzcocks were playing,and that Mk8 had no calibration,so.....