Earth loop

[sparky147]

just finnished installing 5 x rcd sockets using 4mm cable run 60 meters using a 32amp type c mcb and getting a reading of 1.06 what would be the possible cause of the high reading

 

[malcolmsanford]

poor connections,
if your taking the R1+R2( assume that is what this is) via a socket adaptor through the RCD sockets, false reading.
have you nulled the leads

 

[telectrix]

not a high reading. what csa is the cpc? a 60m run of 4.0/1.5mm should give a value for R1+R2 of around 1.2ohms.

 

[sparky147]

really carefull with all my conections will check again, also i didnt null the leads they read at 0.10 but it will still be to high as the max your aloud is 0.72 also the cpc is 4mm thanks, do i need to connect block all rcd sockets then test

 

[davelerave]

ya-it's prob not higher than expected

-ambitious trying to get a C32 on that length of radial

- prob as well to de-rate the circuit anyhow due to VD

 

[sparky147]

thats why i used 4mm cable and not 2.5 as i was worried about the volt drop

 

[malcolmsanford]

60 mts radial in 4mm/4mm will give you a R1+R2 of .55 ohm so yes your well over that. What I would do is just what you said remove the RCD sockets and choc block the cables and see what you get.

 

[telectrix]

even 4.0/4.0mm will gbive R1+R2 of around 0.6ohms at 60m. is a c type MCB essential. ? can you not use a type B?

 

[telectrix]

malc., is it me or you that's a dec. place out. ?

 

[malcolmsanford]

me lol .......0.55ohms

Your on fire today old mate ........sizzle sizzle

 

[telectrix]

all depends on the Ze. not sure if the op meant he was reading Zs. or R1+R2,

 

[telectrix]

me lol .......0.55ohms

Your on fire today old mate ........sizzle sizzle

LOL. i've got a copy of " useful info" from a thread ages ago. part of it gives R1+R2 values for different cables and lengths, up to 50m for T/E, and 25m for SWA. had to extrapolate a bit to guesstimate 60m.

 

[davelerave]

my bad anyway- i just assumed it was a Zs reading

still be too high anyhow

 

[malcolmsanford]

You should test all circuits Before carrying out the work.If the circuit is faulty then it can be charged for .Either way you need to check every circuit as per the installation

?????????????

 

[telectrix]

?????????????

think he's trying to build up his number of posts with anything that comes to mind. have you seen all those threads by jhoncina. bloody rubbish.