Bertram31.com General Bulletin Board

Checking resistance in wires

Posted By: Vic Roy
Date: Tuesday, 3 January 2006, at 6:44 p.m.

In Response To: Re: Electrical Failure nearly sinks Shambala *LINK* (Rocket)

A multimeter checks the ohms (resistance) in a wire by running a tiny current thru the wire from an internal battery in the meter. The drift is that it is not checking the resistance under a real load that might heat up any bad spots in the wire. Usually spots that are partially broken or corroded will heat up and as they do so, increase the resistance. Most of our multimeters just basically test for continuity at tiny 9V. DC current loads. I have a real sensitive one, a "BK Test Bench 388A" that has 400 ohms as its most sensitive scale. I took about 18" of #14 auto primary wire, new looking, and it tested at 0.5 ohms, the same as just holding the two probes together. Then I took about 10 feet of the same wire and it measured 0.6 ohms. So there is not much resistance in wire that's not under a load. Point is, if there is one here, that just checking for resistance in a static (no big load) condition means little. I have found bad spots in wires by touching the ends to a 12v battery and seeing where it heats up. Be careful, cause if done for more than a second or 2 will make the wire into a light bulb. Most of the time the problem is in the end connections where the lug was not soldered or if a plain ole crimp, not heat shinked and/or treated with Penetrox.

Slow night before the ball game, so thought I'd give the Faithful some yawn time.

UV

Messages In This Thread

Electrical Failure nearly sinks Shambala *PIC*
JohnV8r -- Monday, 2 January 2006, at 6:56 p.m.

Here's the picture of the jumper wire *PIC*
JohnV8r -- Monday, 2 January 2006, at 6:58 p.m.

Here's a better picture of the water level *PIC*
JohnV8r -- Monday, 2 January 2006, at 7:29 p.m.

Re: Here's a better picture of the water level
John Frye -- Monday, 2 January 2006, at 7:43 p.m.

Re: Here's a better picture of the water level
Vic Roy -- Monday, 2 January 2006, at 7:57 p.m.

Re: Here's a better picture of the water level
Chiles -- Monday, 2 January 2006, at 8:09 p.m.

Re: Here's a better picture of the water level
JohnV8r -- Tuesday, 3 January 2006, at 12:42 a.m.

Re: Here's a better picture of the water level
JP -- Monday, 2 January 2006, at 9:28 p.m.

Re: Here's a better picture of the water level
peter fallon -- Monday, 2 January 2006, at 9:59 p.m.

Re: Here's a better picture of the water level *PIC*
JohnV8r -- Tuesday, 3 January 2006, at 12:24 a.m.

Re: Here's a better picture of the water level
peter fallon -- Tuesday, 3 January 2006, at 9:29 a.m.

Re: Here's a better picture of the water level
JohnV8r -- Tuesday, 3 January 2006, at 9:41 a.m.

Re: Here's the picture of the jumper wire
andre fourrier-Louisiana -- Monday, 2 January 2006, at 7:55 p.m.

Re: Here's the picture of the jumper wire
Vic Roy -- Monday, 2 January 2006, at 8:02 p.m.

Re: Here's the picture of the jumper wire
Chiles -- Monday, 2 January 2006, at 8:11 p.m.

Re: Here's the picture of the jumper wire
Al Lupone -- Monday, 2 January 2006, at 8:20 p.m.

Re: Here's the picture of the jumper wire
Sean Burlingham -- Monday, 2 January 2006, at 8:30 p.m.

Re: Here's the picture of the jumper wire
JohnV8r -- Monday, 2 January 2006, at 8:56 p.m.

Re: Here's the picture of the jumper wire
JohnV8r -- Monday, 2 January 2006, at 8:45 p.m.

Re: Here's the picture of the jumper wire
Tony Meola -- Monday, 2 January 2006, at 9:33 p.m.

Re: Electrical Failure nearly sinks Shambala
Wayne -- Monday, 2 January 2006, at 8:21 p.m.

Re: Electrical Failure nearly sinks Shambala
Tony Meola -- Monday, 2 January 2006, at 8:41 p.m.

Re: Electrical Failure nearly sinks Shambala
Rawleigh -- Tuesday, 3 January 2006, at 1:06 a.m.

Re: Electrical Failure nearly sinks Shambala
JohnV8r -- Tuesday, 3 January 2006, at 3:06 a.m.

Re: Electrical Failure nearly sinks Shambala
Rawleigh -- Tuesday, 3 January 2006, at 8:51 a.m.

Re: Electrical Failure nearly sinks Shambala
Alex Moore -- Tuesday, 3 January 2006, at 10:16 a.m.

Re: Electrical Failure nearly sinks Shambala
Walter Kaprielian -- Tuesday, 3 January 2006, at 2:55 p.m.

Re: Electrical Failure nearly sinks Shambala
Chiles -- Tuesday, 3 January 2006, at 3:26 p.m.

Re: Electrical Failure nearly sinks Shambala *LINK*
Rocket -- Tuesday, 3 January 2006, at 3:42 p.m.

Checking resistance in wires
Vic Roy -- Tuesday, 3 January 2006, at 6:44 p.m.

Re: Checking resistance in wires
Rocket -- Tuesday, 3 January 2006, at 7:01 p.m.

Re: Electrical Failure nearly sinks Shambala
Rawleigh -- Tuesday, 3 January 2006, at 7:29 p.m.

Re: Electrical Failure nearly sinks Shambala
Rumrunner -- Tuesday, 3 January 2006, at 11:22 p.m.