NO switch insulation resistance failure

[sysrq]

How often do we usually have insulation resistance failures on an NO switches leading to unexpected starts?

 

[telectrix]

dunno about that, but i get insulation failures in my underpants leading to unexpected farts.

 

[buzzlightyear]

dunno about that, but i get insulation failures in my underpants leading to unexpected farts

when was the last gas safety check done on that Tel!

 

[westward10]

Can you explain what you mean.

 

[static zap]

How often do we usually have insulation resistance failures on an NO switches .....

Are they IP rated for the environment... Too vague ..
Regular testing , inspection regime , old reliable /any equivalent replacements fitted ....many things to consider
( the propper answer would be by a paid report ! )

 

[MJPD29]

I don't understand where insulation resistance fits into a NO button failing

 

[Octopus]

Is this a college question?

 

[ipf]

Baffled!

 

[sysrq]

Is this a college question?

No, from a real world experience.

 

[sysrq]

I don't understand where insulation resistance fits into a NO button failing

When the voltage is high enough some leakage current develops between the terminals.

 

[ipf]

No, from a real world experience.

Oh.......I thought you meant normally open..

 

[buzzlightyear]

No, from a real world experience

please explain?

 

[MJPD29]

How High does the voltage have to be? I presume more than 400v

When the voltage is high enough some leakage current develops between the terminals.

 

[sysrq]

How High does the voltage have to be? I presume more than 400v

Don't know the exact voltage this time but sometimes 24 V is enough.

 

[Pete999]

How often do we usually have insulation resistance failures on an NO switches leading to unexpected starts?

Pardon?

 

[Richard Burns]

Any switch that is being run at its rated voltage and current should not experience any flash over, however switches do fail at times.
A common type of failure is for a switch to weld itself closed and therefore could cause the sort of problem you are describing if there are other parts of the circuit holding off power from the switch until a certain point in a process.
For a switch to fail such that it spontaneously conducts I would expect would be rare unless the switch managed to develop point contact surfaces through contact erosion.
However if there are metal dust particles about or frequent arcs on switching generating carbon residue or copper vapour depositing over the enclosure then it may happen.

 

[static zap]

Manual switch ?
Industrial / House hold conditions?
What is the load ? (inductive / lamp / motor - Pure resistance)
..we have barely starter ...!
( Un expected - I would be dusting for fingerprints !)

 

[sysrq]

Any switch that is being run at its rated voltage and current should not experience any flash over, however switches do fail at times.
A common type of failure is for a switch to weld itself closed and therefore could cause the sort of problem you are describing if there are other parts of the circuit holding off power from the switch until a certain point in a process.
For a switch to fail such that it spontaneously conducts I would expect would be rare unless the switch managed to develop point contact surfaces through contact erosion.
However if there are metal dust particles about or frequent arcs on switching generating carbon residue or copper vapour depositing over the enclosure then it may happen.

Another reason why using low voltage ohmmeter alone during troubleshooting is never enough. By using the most basic logic this kind of fault should be resolved in the matter of few minutes.
I wonder how often this kind of fault develops on more dangerous machinery. Couldn't find anything convincing by quick Google search.

 

[sysrq]

Manual switch ?
Industrial / House hold conditions?
What is the load ? (inductive / lamp / motor - Pure resistance)
..we have barely starter ...!
( Un expected - I would be dusting for fingerprints !)

Inductive load in the form of contactor coil.

 

[PEG]

Another reason why using low voltage ohmmeter alone during troubleshooting is never enough. By using the most basic logic this kind of fault should be resolved in the matter of few minutes.
I wonder how often this kind of fault develops on more dangerous machinery. Couldn't find anything convincing by quick Google search.

...Or twenty or so posts,should do it