110v solinoid valve

Jako13! · Oct 12, 2020

Got a question regarding a solinoid. I measured between the earth pin and the body of the solinoid valve in question with my multimeter to find a high resistance reading I again tested another valve by the same manufacturer and again it had a high reading why would this be?

This is the valve

https://uk.rs-online.com/mobile/p/solenoid-valves/8732556/

Thanks guys

DPG · Oct 12, 2020

Surely the coil resistance would be correct when measured between the coil terminals though. Am I missing something here?

Jako13! · Oct 12, 2020

DPG said:
Surely the coil resistance would be correct when measured between the coil terminals though. Am I missing something here?

Sorry I meant a high resistance Earth

Lucien Nunes · Oct 12, 2020

The brass body of the valve probably doesn't need to be earthed as it's not electrical and can't become live by itself in the event of a fault. The earth terminal is likely to be connected solidly to some part of the solenoid innards that will intercept any fault before it can make the valve body live. There is probably casual contact between the two, hence you do get some sort of a continuity reading to the external metalwork.

It's like a deep fat fryer that has an earth connection to the element but not to the tank. The tank could only become live if the element became live, and that won't happen because the element is earthed. But the two are in contact so you'll get a reading.

Jako13! · Oct 12, 2020

Lucien Nunes said:
The brass body of the valve probably doesn't need to be earthed as it's not electrical and can't become live by itself in the event of a fault. The earth terminal is likely to be connected solidly to some part of the solenoid innards that will intercept any fault before it can make the valve body live. There is probably casual contact between the two, hence you do get some sort of a continuity reading to the external metalwork.

It's like a deep fat fryer that has an earth connection to the element but not to the tank. The tank could only become live if the element became live, and that won't happen because the element is earthed. But the two are in contact so you'll get a reading.

Thank you ?

Marvo · Oct 13, 2020

As Lucien said the earth pin of the coil is usually connected to the iron sleeve in the centre of the coil. The iron sleeve may or may not make contact with the body of the valve when it's assembled. In most newer valves the entire coil and the sleeve is potted in resin. With some of the older solenoids like the Asco ones the coil is potted but the sleeve on the inside is still visible and it usually does make contact with the valve body via the anti-buzz spring washer and the retaining nut.