what do you make of this???

[avinalarf]

whether TT TNS TNCSthe final circuits.. R1+R2 INS RES etc...

would all be of "standard" type values appropriate to the lengths of cables used.

the TT bit only relates upon the external earth bit & Zs.

i.e.

TNS/TNCS Zs=Ze+(R1+R2)

TT Zs=Ra+(R1+R2)

Big SIGH - so at least my Zs result of 80+ohm is ok then.

so back to your cables???? :_|

Think you need to go back and check shorter sections of the cable,

may be a crap joint somewhere.

A wander lead may be helpful in this situation?

Ok, will do some checks tomorrow. Forgive my ignorance, but I thought the wander lead was only really useful for checking bonding Blushing

 

[Andy™]

3-core SWA was joined to circuit via a JB.Is that possible over such a short distance? The only thing that separates these 2 sockets is the wood panels of the shed!

cables can be faulty at any point, so yes, it could be in that short section

Is this bad?

very bad - in fault conditions, and certain normal conditions, there can be a potential between them

I shall take a reading from the rod outside the shed - had only taken reading from rod for house Blushing.

my red

 

[avinalarf]

So if its a ring what are your values for r1, r2 & rn?

R1 = 0.68

R2 = 1.24

Rn = 0.60

 

[Andy™]

R2 still a little high, and Rn should be closer to R1

 

[avinalarf]

R2 still a little high, and Rn should be closer to R1

That's what I thought

 

[ianmacd]

When was your meter last calibrated?

 

[Andy™]

more importantly, when were batteries replaced

 

[ianmacd]

R1 = 0.68R2 = 1.24

Rn = 0.60

this suggests that the line is about 15% longer than the neutral. What size/type cable is this?

 

[avinalarf]

I've only had the tester since last June. Thought I was getting some funny readings last year, so returned it to manufacturer who said it was fine. Bought the Calcard and only tested it over the weekend - all results were within tolerances.

 

[avinalarf]

more importantly, when were batteries replaced

Funny you should mention that! I changed them today. Should I go over the tests again?

 

[avinalarf]

this suggests that the line is about 15% longer than the neutral. What size/type cable is this?

It's T&E 2.5/1.5.

 

[ianmacd]

Funny you should mention that! I changed them today. Should I go over the tests again?

I think so.

 

[ianmacd]

It's T&E 2.5/1.5.

Then r2 should have been nearer 1.6x r1 or rn not more than double. Its not 2.5/1.0 then?

 

[Andy™]

Funny you should mention that! I changed them today. Should I go over the tests again?

may be a good idea. low batteries can give some dodgy readings way before the low battery warning comes up

 

[avinalarf]

Then r2 should have been nearer 1.6x r1 or rn not more than double. Its not 2.5/1.0 then?

So if I've over-estimated cpc size, what would the multiple be for r1 if cpc is 1mm?

 

[avinalarf]

may be a good idea. low batteries can give some dodgy readings way before the low battery warning comes up

That's useful to know Applaud Smiley. With that in mind, when's the best time to change the batteries then? What should I use as a guide on the Fluke 1652 when doing a battery test?

 

[Andy™]

So if I've over-estimated cpc size, what would the multiple be for r1 if cpc is 1mm?

2.5/1

=2.5

 

[Andy™]

That's useful to know Applaud Smiley. With that in mind, when's the best time to change the batteries then? What should I use as a guide on the Fluke 1652 when doing a battery test?

change as soon as you get a reading that doesnt look right, and you get different readings doing the same test on same conductor

 

[avinalarf]

2.5/1=2.5

Oh Blushing.

Well, I obviously can't rely on any of today's tests, so shall do them all again tomorrow.

 

[ianmacd]

Good luck.