Spot the mistake

[ricicle]

Part of somebody else's test results I viewed today - can anybody spot a possible problem.


Ring final circuit, single cables, 2.5mm² P+N, 1.5mm² cpc.
32A protective device.
End to end Phase resistance 1.02 ohms
End to end Neutral resistance 1.02 ohms.

etc etc etc

 

[Spark123]

The phase and neutral end to end resistances are reading the same which is correct. I'd expect an R1+R2 of somewhere around 0.68 ohms providing it isn't in metalic conduit etc. Maximum tabulated Zs is 1.5ohms for assuming a B32 MCB, 1.2 ohms max measured. Providing the Ze is low enough it is fine.

 

[bengasman]

one problem could be that the question seems to be missing

 

[EdwardCurrent]

IR may be high on R2

supp bonding

 

[ricicle]

one problem could be that the question seems to be missing

can anybody spot a possible problem.

 

[securespark]

Does the resistance seem a little on the high side, suggesting an expansive circuit?

 

[Spark123]

I'm thinking it may be a little bit high on volt drop if all the loading is at the mid point?

 

[ricicle]

Does the resistance seem a little on the high side, suggesting an expansive circuit?

Top of the class Mr Secure.

From my calculations the resistance of 2.5 (@20 deg) is 7.41mOhms/M

The circuit equates to around 141 metres.Lets say one of the double sockets at around mid point draws 20A.The VD of 2.5 singles in this instance is 18mV/A/M.Each even leg would draw 10A, 70.5M to mid point

(18*10*70.5)/1000 = 12.69V

That is without the VD of the sub-main to the DB feeding the circuit.

Scooby snack to 123 also

 

[reggie perrin]

Part of somebody else's test results I viewed today - can anybody spot a possible problem.


Ring final circuit, single cables, 2.5mm² P+N, 1.5mm² cpc.
32A protective device.
End to end Phase resistance 1.02 ohms
End to end Neutral resistance 1.02 ohms.

etc etc etc

32A MCB max Zs 1.2...

 

[securespark]

Top of the class Mr Secure.

I thank you!!

Scooby snack to 123 also

OK, fair 'nough, I s'pose.....