Crappy Brymen test leads for the Brymen BM878 insulation meter or is it me? - Page 1
Forum section: electronics / beginners

author: rjardina
author_rank: Contributor
timestamp: July 04, 2016, 03:12:13 am
content: I have the BM878 and was having random issues with it and I was getting frustrated with it.Until I found the problem and its with the probes that came with the meter.The meter came with a set of black and red double insulated 1KV probes, and aninsulation test probe with a test button on it, for easier use. It has the same ratingas the black and red probe set nor do I have an issue with that one just the normalblack and red probe set.I would get issues with it under the 1000 volt test. The problem is when the wires of theprobes touch one another or when they're touch something together that is conductive. I willget readings as low as 400M ohms. The probe tips are isolated in the air.Now if I replace those probes with my Fluke TL224 leads and using the Fluke TL175 probesIf I crumble the tests leads in a ball together and keeping the probes isolated. The BM878reads the max of > 25G Ohms like it should. I'm placing the fluke probes in a worserscenario.I have three set of these Brymen test probes and two of which I have this problem with. To befair on the third set that I don't have this issue with They're brand new and been sitting in a bag.obviously, I wouldn't be using them for this function of the meter any longer. But I mainly dealwith mains. So safety is a biggest factor for me. Or are this just land field material.

author: coppice
author_rank: Super Contributor
timestamp: July 04, 2016, 03:41:48 am
content: Have you tried cleaning them thoroughly? Dirty leads generally leak, but leads fresh out of the box sometimes leak due to manufacturing residues on them.

author: retiredcaps
author_rank: Super Contributor
timestamp: July 04, 2016, 04:54:23 am
content: Quote from: rjardina on July 04, 2016, 03:12:13 amI suggest sending an email to Brymen viahttp://www.brymen.com.tw/product-html/index.html#CONTACTI contacted them for some info to replace some input protection components and much to my surprise, they answered my email with the values within 24 hours.Let me know about your issue and see what they have to say.

author: rjardina
author_rank: Contributor
timestamp: July 04, 2016, 09:16:49 pm
content: Quote from: coppice on July 04, 2016, 03:41:48 amHow would you recommend cleaning them? I tried isopropyl alcohol. Only effect is that they looked better.I can somewhat understand that the cleanliness of the probes would have an effect, But wouldn't it have topierce or sink into the insulation, or what ever is coating the lead would have to run the full length and endup touching the probes ends?I will also try contacting brymen,

author: coppice
author_rank: Super Contributor
timestamp: July 05, 2016, 01:56:55 am
content: Quote from: rjardina on July 04, 2016, 09:16:49 pmA dirty patch won't cause harm, but a grimy film from end to end of the cable can form a parallel conductive path between the terminals at the ends. Touch that and you have leakage. Most really high impedance stuff needs to be kept clean.If you have cleaned these leads with isopropanol, and they look good now, your problem probably lies elsewhere.

author: rjardina
author_rank: Contributor
timestamp: July 06, 2016, 11:27:08 am
content: My reply from BrymenQuoteI was using the wrong pair of probes, the third set that were new that I didn't have an issue with. Did have the screw tips. (I didn't even know they had screw tips until I took the damn probe caps off.)When I got the meter I just tossed them in a bag didn't think there was a differences.The three Brymen meters I have BM869s and BM089 both come with PVC wire probes and the BM878 come with Silicon. I guess the whole time it was me.