zs testing

[LeeH]

Bonding should be, yes. What other kinds of parallel paths could there be, bearing in mind during testing anything not relevant to the testing should be disconnected?

You're saying you disconnect parallel paths apart from bonding while taking a measurement? Good luck with that outside of a 2 up 2 down!

A list of parallel paths is endless. Motor sat on a steel platform for example. Try disconnecting that while measuring Zs.

My point is, parallel paths come and go during the life of the install. The CPC is there to stay so why having a worst case scenario such a bad thing?

For example, man fits motor, motor vibrates, man fits anti vibration feet, parallel path lost, Zs increases. Disconnection time now not achieved.

I'm not saying it's better, just cannot understand some people's resistance to calculate.

 

[Adam W]

You're saying you disconnect parallel paths apart from bonding while taking a measurement? Good luck with that outside of a 2 up 2 down!

A list of parallel paths is endless. Motor sat on a steel platform for example. Try disconnecting that while measuring Zs.

My point is, parallel paths come and go during the life of the install. The CPC is there to stay so why having a worst case scenario such a bad thing?

For example, man fits motor, motor vibrates, man fits anti vibration feet, parallel path lost, Zs increases. Disconnection time now not achieved.

I'm not saying it's better, just cannot understand some people's resistance to calculate.

The original question was about a college question, but if a Zs were likely to be increased the person likely to be increasing it should measure the Zs when he alters it.
Similar questions have come up before, and the general consensus is you can't account for alterations which may be made.

 

[LeeH]

You can when only the CPC is in the equation.

I know, I'm playing devils advocate.

 

[Adam W]

You can when only the CPC is in the equation.

I know, I'm playing devils advocate.

What if you were using metallic containment as the CPC?

 

[Engineer54]

You're saying you disconnect parallel paths apart from bonding while taking a measurement? Good luck with that outside of a 2 up 2 down!

A list of parallel paths is endless. Motor sat on a steel platform for example. Try disconnecting that while measuring Zs.

My point is, parallel paths come and go during the life of the install. The CPC is there to stay so why having a worst case scenario such a bad thing?

For example, man fits motor, motor vibrates, man fits anti vibration feet, parallel path lost, Zs increases. Disconnection time now not achieved.

I'm not saying it's better, just cannot understand some people's resistance to calculate.

Why arse around calculating when you can directly test/measure the Zs at any given point on the circuit, and get an accurate value into the bargain!!!

 

[Adam W]

Why arse around calculating when you can directly test/measure the Zs at any given point on the circuit, and get an accurate value into the bargain!!!

Because it can be safer, but it seems we're going around in circles now.

 

[Engineer54]

Because it can be safer, but it seems we're going around in circles now.

Listen, ...if you can't safely undertake Ze/Zs tests or any other live testing, then there's something very wrong and shouldn't be in this industry. Live testing is a fundamental necessity for assessing electrical installations, end of!! I'm not going round in circles, i've stated previously i would not accept a calculated value, it's either a directly tested value or Nothing!!...

 

[Adam W]

Listen, ...if you can't safely undertake Ze/Zs tests or any other live testing, then there's something very wrong and shouldn't be in this industry. Live testing is a fundamental necessity for assessing electrical installations, end of!! I'm not going round in circles, i've stated previously i would not accept a calculated value, it's either a directly tested value or Nothing!!...

Depends on the circumstances.

 

[Adam W]

Listen, ...if you can't safely undertake Ze/Zs tests or any other live testing, then there's something very wrong and shouldn't be in this industry. Live testing is a fundamental necessity for assessing electrical installations, end of!! I'm not going round in circles, i've stated previously i would not accept a calculated value, it's either a directly tested value or Nothing!!...

Who said anything about Ze? Why would you not be able to take a live Ze reading? And how else would you take it?

 

[LeeH]

Listen, ...if you can't safely undertake Ze/Zs tests or any other live testing, then there's something very wrong and shouldn't be in this industry.

There IS something very wrong with the industry unfortunately.

What if you were using metallic containment as the CPC?

Measure is the only solution.

Why arse around calculating when you can directly test/measure the Zs at any given point on the circuit, and get an accurate value into the bargain!!!

Because it can take hours to get ISO locks taken off and reinstated.

And you can get accurate results with a brew in your hand rather then an MFT.