Strange event in my workshop? - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Radio Wrangler · 11th Jul 2018, 10:43 am

With 100 Ohms, I don't suppose a megger will develop enough voltage to do anything.

I was going to suggest unplugging things to see what might clear it, but that's already been covered.

David

Graham G3ZVT · 11th Jul 2018, 12:09 pm

I once had a mystery low resistance reading between live and earth on one of my house wiring circuits, which tripped the RCD whenever the MCB for that circuit was closed.

I was surprised when I eventually tracked down the fault. A chain of carbonised ants forming a U-link between two terminals of my central heating wiring centre.

The Philpott · 11th Jul 2018, 12:44 pm

That doesn't surprise me! 'Bugs live in plugs' for some reason. The number of times i have found small spiders living (happily) in junction boxes... possibly because larger spiders can't get in and duff them up.

A pipe finder/power finder might be helpful to Paul. Less so if the shelf brackets are metallic.

HamishBoxer · 11th Jul 2018, 12:55 pm

We all wait with interest as to the reason at the end of the day.

Skywave · 11th Jul 2018, 1:13 pm

Quote:

Originally Posted by Station X

Surely the resistance of 10 foot of wire is negligible and the 100 ohm earth fault could be at any point on the wire?

Yes, agreed. I was thinking too hard about this.

Al.

kalee99 · 11th Jul 2018, 1:58 pm

Hi all,
Yes the resistance of the wire from end to was less than 1Ω so good continuity. but measuring from either end to the mains Earth it was almost exactly 100Ω No mains voltage detected on the wire and running my 500 volt megger still gave a steady 100Ω. Some of the stuff on the shelves has not been moved for years but non of it is in anyway plugged into the mains or anything else. As the shelves are not moving any time soon it will just have to go down as one of life's great mysteries.
Paul.

Station X · 11th Jul 2018, 2:14 pm

Quote:

Originally Posted by kalee99

The 10 ft. bit of wire to my workbench that just runs along the wall behind my wooden shelving was the guilty party with 100Ω to earth on either end.

It’s just a bit of insulated wire...……... Paul.

Is the wire fixed to anything by staples or W.H.Y or does it dangle freely?

ms660 · 11th Jul 2018, 2:16 pm

I wonder if it was Tee'd off years ago and long forgotten?

Lawrence.

11th Jul 2018, 10:43 am	#21
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,858	Re: Strange event in my workshop? With 100 Ohms, I don't suppose a megger will develop enough voltage to do anything. I was going to suggest unplugging things to see what might clear it, but that's already been covered. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

11th Jul 2018, 12:09 pm	#22
Graham G3ZVT Dekatron Join Date: May 2010 Location: Greater Manchester, UK. Posts: 18,710	Re: Strange event in my workshop? I once had a mystery low resistance reading between live and earth on one of my house wiring circuits, which tripped the RCD whenever the MCB for that circuit was closed. I was surprised when I eventually tracked down the fault. A chain of carbonised ants forming a U-link between two terminals of my central heating wiring centre. __________________ -- Graham. G3ZVT

11th Jul 2018, 12:44 pm	#23
The Philpott Dekatron Join Date: Aug 2016 Location: Colchester, Essex, UK. Posts: 4,103	Re: Strange event in my workshop? That doesn't surprise me! 'Bugs live in plugs' for some reason. The number of times i have found small spiders living (happily) in junction boxes... possibly because larger spiders can't get in and duff them up. A pipe finder/power finder might be helpful to Paul. Less so if the shelf brackets are metallic.

11th Jul 2018, 12:55 pm	#24
HamishBoxer Dekatron Join Date: Aug 2007 Location: W.Butterwick, near Doncaster UK. Posts: 8,931	Re: Strange event in my workshop? We all wait with interest as to the reason at the end of the day. __________________ G8JET BVWS Archivist and Member V.M.A.R.S

11th Jul 2018, 1:58 pm	#26
kalee99 Rest in Peace Join Date: Dec 2004 Location: Newcastle Upon Tyne, Tyneside, UK. Posts: 420	Re: Strange event in my workshop? Hi all, Yes the resistance of the wire from end to was less than 1Ω so good continuity. but measuring from either end to the mains Earth it was almost exactly 100Ω No mains voltage detected on the wire and running my 500 volt megger still gave a steady 100Ω. Some of the stuff on the shelves has not been moved for years but non of it is in anyway plugged into the mains or anything else. As the shelves are not moving any time soon it will just have to go down as one of life's great mysteries. Paul.

11th Jul 2018, 2:16 pm	#28
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Strange event in my workshop? I wonder if it was Tee'd off years ago and long forgotten? Lawrence.