Burnt Main Downstream Neutral

[static zap]

Still confused with order
Ring Final returned

0 and 5.5 and-- 5 MegOhms ...
L-E, ..L-N and N-E...?
If N-E have not been isolated L&N swapped ..
(or is it just LE,LN&NE sequence off)

 

[westward10]

I don't find it confusing.

 

[ennaress]

Zero was the reading for Ring Final between Line/Earth. 5.5MOhms was the reading for Line/Neutral. 5 MOhms N-E. c.350 MOhms or thereabouts for the other circuits. This was a soft test (250V) - and yes I know what 7671 says...but disconnecting all loads was not practical at the time. I knew the CU would have to be replaced and that the circuitry was shot due to the burnt N bar so I hoped a soft test would suffice knowing a new CU would then have to be fully tested with 500V DC.

 

[westward10]

If you haven't disconnected all loads how have you got a L/N reading and differing L/E and N/E readings. You should have used 500v it would have done no harm.

 

[DPG]

But the zero ohm reading shows that there is either a fault or something is still plugged in. Without unplugging everything how will you know which it is? The test result is meaningless.

 

[HandySparks]

But the zero ohm reading shows that there is either a fault or something is still plugged in. Without unplugging everything how will you know which it is? The test result is meaningless.

Not entirely meaningless. Just not the value you would have hoped for. If you can get an acceptable IR value with appliances connected, you know it's going to be OK without them. Obviously, if the IR's too low then further investigation required.

 

[DPG]

Not entirely meaningless. Just not the value you would have hoped for. If you can get an acceptable IR value with appliances connected, you know it's going to be OK without them. Obviously, if the IR's too low then further investigation required.

But he hasn't got acceptable values.

 

[westward10]

It is odd he hasn't got zero both sides to earth but he also has a reading for L/N.

 

[HandySparks]

But he hasn't got acceptable values.

Quite agree. Hence the need for more testing.

 

[DPG]

Quite agree. Hence the need for more testing.

Indeed. As I said, stuff needs unplugging and then some proper testing doing.

 

[mrloy99]

The burnt neutral looks to me to be on the lighting circuit..must have been loose.
I would agree that all would need to be unplugged for IR test and the imm htrs would need to be switched off if double pole switch or disconnected if only single pole kit eg some spurs maybe for washing machine?

Wonder what live to earth on ohm scale showed?