EFLI - measure or calculate?

[kingeri]

Just wondering what you guys generally do to determine the EFLI of a circuit during testing. Do you calculate it, as in Zs=Ze+(r1+r2), or do you measure for each circuit, or both. I tend to calculate it these days, simply as it's quicker, but just wondered what others do.

 

[Deleted member 72666]

Measure every time.

 

[JC94]

Usually with RFCs I just stick the megger in and let it do all the hard work, then for anything such as lighting, boiler etc where it'd be considered working live/near live parts (Naughty) I calculate but put a little * on the cert with a note at the bottom noting calculated values

 

[LeeH]

Calculate every time for me.

 

[HandySparks]

... then for anything such as lighting, boiler etc where it'd be considered working live/near live parts (Naughty) I calculate but put a little * on the cert with a note at the bottom noting calculated values

Not naughty at all. How do you get your Ze then? By enquiry? :laugh3:

Measure every time for me. It's a good check that everything's been re-connected as it should be, especially if you do a Z l-n at the same time to check the neutral.

 

[mhar]

Both. Calculate first to give worst case scenario (before parallel paths) and enter on cert then measure last point on each circuit at the end to make sure this is less than or equal to the calculated value and that everything has been reconnected properly

 

[Octopus]

Measure every time.

 

[MDJ]

Sparks measure

 

[Silly Sausage]

Sparks measure ...... up to what?

.......

 

[SirKit Breaker]

It is all well and good calculating it, but it doesn't prove that you have an earth, testing it does. I know calculation is acceptable, but measurement is better if you think about it, and although Ze =Zs +(R1+R2], a measured result will always be a bit lower (or should be) due to parallel paths, and the current that the tester is forcing around the circuit.

Cheers……………..Howard

 

[telectrix]

Sparks measure- wussies calculate.

corrected that post for you.

 

[LeeH]

It is all well and good calculating it, but it doesn't prove that you have an earth, testing it does. I know calculation is acceptable, but measurement is better if you think about it, and although Ze =Zs +(R1+R2], a measured result will always be a bit lower (or should be) due to parallel paths, and the current that the tester is forcing around the circuit.

Cheers……………..Howard

And that's why it's better to calculate.

Parallel paths come and go, and you have already proven you have an earth so I don't agree with you at all.

 

[MDJ]

.......

Hey calm down now LOL

 

[telectrix]

calm down, calm down.....

 

[Octopus]

And that's why it's better to calculate.

Parallel paths come and go, and you have already proven you have an earth so I don't agree with you at all.

A brave man to disagree with SirKit Breaker!

 

[Billythekid]

Measure.

It is possible that your low current Continuity tester will indicate a sound connection, whilst the high current Loop Impedance tester will expose a possible weakness.

Regards

Billy

 

[Silly Sausage]

Hey calm down now LOL

What's with scousers fiddling with my posts?!?!


Live Zs every time!

 

[kingeri]

If you've proven continuity and measured your Ze, then calculating Zs is fine by me. But it actually doesn't take that long to measure, so I suppose you just get better piece of mind by doing so.

 

[MDJ]

We discussed this a day or two ago and decided to verify the circuit a measured ZS was needed, can't remember which thread it was now but it made sense afetr reading it all.

 

[Guitarist]

And that's why it's better to calculate.

Parallel paths come and go, and you have already proven you have an earth so I don't agree with you at all.

I do agree with this reasoning, and as a rule I tend to calculate. If there's a lot involved with disconnections for measuring, however, I'll happily measure.