High TNS readingssssss

[Bradley6969]

TNS system
60947-2 main switch
60898 double pole 63amp MCBs that feed some caravan boxes now some circuits I can get below the disconnection times of 0.56 ohms but some are 1.22 ohms now I’ve tried changing glands anything else I can do apart from TT the hook up unit? Or do you need upfront RCD

If not change the distribution unit feeding boxes with RCD and Rod it

 

[Bobster]

So you've installed the wrong size cable then...

 

[Bradley6969]

So you've installed the wrong size cable then...

Not installed anything

 

[westward10]

This is the third thread you have started on this theme.

 

[Bobster]

So what is it your doing? Remedial work?

What are the values on the original EIC?

Is the cable running to the DB SWA?

 

[Bradley6969]

Yes, some values are ok then some are not all SWA some original values are 0.79 ohms need to be below 0.56 ohms

 

[Pete999]

TNS system
60947-2 main switch
60898 double pole 63amp MCBs that feed some caravan boxes now some circuits I can get below the disconnection times of 0.56 ohms but some are 1.22 ohms now I’ve tried changing glands anything else I can do apart from TT the hook up unit? Or do you need upfront RCD

If not change the distribution unit feeding boxes with RCD and Rod it

What R1+R2 readings?

 

[Bradley6969]

What R1+R2 readings?

No dead testing currently occupied

 

[Bobster]

Yes, some values are ok then some are not all SWA some original values are 0.79 ohms need to be below 0.56 ohms

So there's a good chance the SWA is damaged and the Armour is rotting.

Original install wasn't designed correctly.

Time to quote to do the job properly.

 

[Charlie_]

I would arrange a convenient time to turn the power off.
This will then allow you to do the necessary tests