Arthurdent
Member
Hi everyone I have a fun question (ok , depends what you do for fun)
I had some issues with my main rcd that I resolved, but it gave me cause to take a closer look at sources of apparent leakage around the property. At first I thought the boiler (pump etc) might be leaking to earth but ... it seems it's simply the two motorised valve heads leaking to the pipe work / alternate path to ground such that it shows up on a clamp meter.
One is leaking a 1-2mA, the other less than 0.5mA. So I figured I would IR the one that shows the most just in case it's on the way out. I found nothing of note ... it shows > 10 Mohms at 500v. I couldn't find anything else in the case (relay etc) with suspect insulation resistance. With the motor head dangling off the pipe work, the clamp reads 0 which is right, any leakage back up the cpc would cancel out as I haven't split the cable. All back together and on the pipes, the last reading was 1.75 mA leakage & it drifts around.
I am wondering if the leakage is just induction between the windings and the nice aluminium case that it all lives in. The one that shows the most leakage is a Corgi valve head, the one with the least is a Honeywell one. The former is newer. I'm thinking of just swapping the synchro motor in the Corgi one for a fresh one.
Just for general interest at this point tbh, there doesn't seem to be any critical problem to fix, just tinkering etc. Wondered if anyone has seen this before.
I had some issues with my main rcd that I resolved, but it gave me cause to take a closer look at sources of apparent leakage around the property. At first I thought the boiler (pump etc) might be leaking to earth but ... it seems it's simply the two motorised valve heads leaking to the pipe work / alternate path to ground such that it shows up on a clamp meter.
One is leaking a 1-2mA, the other less than 0.5mA. So I figured I would IR the one that shows the most just in case it's on the way out. I found nothing of note ... it shows > 10 Mohms at 500v. I couldn't find anything else in the case (relay etc) with suspect insulation resistance. With the motor head dangling off the pipe work, the clamp reads 0 which is right, any leakage back up the cpc would cancel out as I haven't split the cable. All back together and on the pipes, the last reading was 1.75 mA leakage & it drifts around.
I am wondering if the leakage is just induction between the windings and the nice aluminium case that it all lives in. The one that shows the most leakage is a Corgi valve head, the one with the least is a Honeywell one. The former is newer. I'm thinking of just swapping the synchro motor in the Corgi one for a fresh one.
Just for general interest at this point tbh, there doesn't seem to be any critical problem to fix, just tinkering etc. Wondered if anyone has seen this before.