TNS supply reading query

[stumas]

I've got a TNS supply coming into the building with a reading of 0.76ohms. The maximum is 0.8ohms. On circuit one I have a 3phase socket with a reading of 0.88ohms on a breaker60898 C32, maximum permitted for this breaker is 0.72 ohms which is already below my reading of 0.76. How do I make this comply? (Please excuse any bad electrical terms as this is typed by Mrs. stumas at his request. He needs this information for what he is doing right now at work. Many thanks in advance)

 

[telectrix]

change MCB for B type is 1 option. if he's doing a EICR, then a C3 code , unless circuit is RCD protected, then the max. Zs is 1667 ohms.

 

[KAS1]

Why doesn't he ask his boss ? or is he the boss of his own company? Is this another pretender at work getting a forum to sort his problems for him, well shame on anyone who helps.

 

[KAS1]

This could be a 11 year old you are giving a step by step guide to lol

change MCB for B type is 1 option. if he's doing a EICR, then a C3 code , unless circuit is RCD protected, then the max. Zs is 1667 ohms.

 

[stumas]

No. My husband is a very good electrician and an inspector and tester. He just wants to make sure he does it correctly. Tell me what this forum is for KAS1 if not for a little help when needed? Im sure my husband has helped people before as he has been thanked by the look of it by other people. Yes, I WILL stand up for my husband, as I think your comment is unfair. Thank you telectrix for your reply, I have texted him your reply. I have absolutely no idea what it means but I'm sure he does.

 

[KAS1]

What is the cct wired in?

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What is the installation method?

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What is the air temp?

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Where is he taking his measurements?

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Is the readings calculated or measured?

 

[KAS1]

Why hasn't he got his BGB with him?

I've got a TNS supply coming into the building with a reading of 0.76ohms. The maximum is 0.8ohms. On circuit one I have a 3phase socket with a reading of 0.88ohms on a breaker60898 C32, maximum permitted for this breaker is 0.72 ohms which is already below my reading of 0.76. How do I make this comply? (Please excuse any bad electrical terms as this is typed by Mrs. stumas at his request. He needs this information for what he is doing right now at work. Many thanks in advance)

 

[Engineer54]

It's depending on what that 3 phase socket is supplying as to whether you can change the MCB out for a type B or not.
If you can't, at this stage of the game your only option is to provide that outlet with an RCD device, and ask the client to contact the DNO as to the chances of a PME connection.


Before doing that, check that main earthing conductor for any loose connections, and confirm that Ze value by taking the earth connection directly from the cable sheath, rather than the conductor attached to the sheath. You (and the client) may just be lucky in finding the problem... lol!!

 

[Amp David]

No. My husband is a very good electrician and an inspector and tester. He just wants to make sure he does it correctly. Tell me what this forum is for KAS1 if not for a little help when needed? Im sure my husband has helped people before as he has been thanked by the look of it by other people. Yes, I WILL stand up for my husband, as I think your comment is unfair. Thank you telectrix for your reply, I have texted him your reply. I have absolutely no idea what it means but I'm sure he does.

Doesn't sound like it. Probably a right cowboy :gunsmilie:

 

[stuartcourt]

Doesn't sound like it. Probably a right cowboy :gunsmilie:

why does he sound like a cowboy ? surely a cowboy would just think who cares

 

[MDJ]

I've got a TNS supply coming into the building with a reading of 0.76ohms. The maximum is 0.8ohms. )

is it? I thought it was 0.80?

 

[telectrix]

that's what she said, mike. 0.8, 0.80.

 

[MDJ]

that's what she said, mike. 0.8, 0.80.

I got a little confused, I thought she meant the 0.76 was a problem, after reading it again I see she means there's a problem with out going readings on circuits, cheers Tel

 

[telectrix]

another solution might be to clamp the circuit and measure the current per phase. depending upon what the load is , you may find derating the breaker to 25A or even 20A is possible.