Oh goody, a quiz... C1 or C2???

[Strima]

There is a poll.

So, one of my lads inspected a street cabinet earlier this week and the cover for the neutral is missing on the DNOs head.

This is accessible by normal persons who hold cabinet keys, they are telecoms engineers but may not necessarily be electrically aware.

I have this as a C1.

My reasoning that this is a TT system so there could well be potential difference between the neutral and earth. It's a big metal box PFC of 1kA and an Ra of 74.3 ohms. PEFC of 0.003kA so a nasty nip could be had.

Unfortunately he neglected to get any continuity measurement between neutral and earth.

The customers in house teams says this is a C2. If it was a TNC-S system then I might agree.

What does the mighty collective say?

 

[Pete999]

So, one of my lads inspected a street cabinet earlier this week and the cover for the neutral is missing on the DNOs head.

This is accessible by normal persons who hold cabinet keys, they are telecoms engineers but may not necessarily be electrically aware.

I have this as a C1.

My reasoning that this is a TT system so there could well be potential difference between the neutral and earth. It's a big metal box PFC of 1kA and an Ra of 74.3 ohms. PEFC of 0.003kA so a nasty nip could be had.

Unfortunately he neglected to get any continuity measurement between neutral and earth.

The customers in house teams says this is a C2. If it was a TNC-S system then I might agree.

What does the mighty collective say?

View attachment 46386

C1

 

[buzzlightyear]

c1 for me

 

[Risteard]

As the neutral conductor is a live conductor essentially what is there is exposed live parts. As you suggest the situation is somewhat more complex with a TN system as this is reliably connected to Earth (however remains by definition a live part - unless it is a PEN conductor as this conventionally is not considered to be a live conductor).

 

[gazdkw82]

C1. Exposed live conductor

 

[cprfenom]

C1 for me as it is classed as a live conductor. Only point maybe is that to get in to the cabinet requires a tool or key? By that reason some may consider it an C2?

 

[Strima]

C1 for me as it is classed as a live conductor. Only point maybe is that to get in to the cabinet requires a tool or key? By that reason some may consider it an C2?

That was one of their arguments however any engineer with keys can access it but they may not be electrically aware hence my reasoning for a C1.

 

[cprfenom]

That was one of their arguments however any engineer with keys can access it but they may not be electrically aware hence my reasoning for a C1.

I think I would agree with that as the meter is in there. Had it not been then maybe a C2 could be justified

 

[telectrix]

I think I would agree with that as the meter is in there. Had it not been then maybe a C2 could be justified

so does that mean we're not allowed to electrocute meter muppets any more?

 

[chris gray]

Access to live parts is only possible with the use of a tool. I’d like to think there are signs stating the potential risks and therefore only competent persons should be gaining access to the locked cupboard.

 

[littlespark]

Just replace the cover, and stop asking questions.

 

[Wilko]

Inside domestic boards the neutral bar is exposed and we can open them with a normal screwdriver. Or have I missed something.
Edit - yes - I isolate the board with DP switch before opening it .

 

[Nigel]

C2 in a locked cabinet.

 

[Nigel]

That was one of their arguments however any engineer with keys can access it but they may not be electrically aware hence my reasoning for a C1.

Disagree. Anyone has a screwdriver but we do not C1 DBs.

 

[buzzlightyear]

C2 in a locked cabinet.

when you open its not, safety for some one .

 

[UKPN]

Forgive me, but the DNO equipment comes under ESQCR regs, BS7671 doesn't apply. The DNO should be contacted. In any event, if this was PME and a 16mmsq was connected from the neutral to an earth block on the meter board you wouldn't think twice about it.

 

[buzzlightyear]

Forgive me, but the DNO equipment comes under ESQCR regs

so it does not come under heath and safety then .

 

[Nigel]

when you open its not, safety for some one .

And ai get that but something needs to happen for it to be immediatky dangerous. As in the cabinet needs to be unlocked and opened. There is no way this could be deemed as ‘immediately dangerous’.

 

[Strima]

This is why we can never have nice things as we never agree.

But this kind of debate is good, there are so many variables with this kind of situation there are so many possibilities and outcomes.

So not a C3 then???

As UKPN has pointed out this is DNO equipment and comes under ESQCR but yet on the model forms in BS7671 on the schedule of inspections we are asked to inspect the DNO equipment for faults and report accordingly.

Damned if we do, damned if we don't.

 

[Nigel]

There is no doubt that this is covered by BS7671. Only the most irresponsible or lazy electricians would not code this in some way.

My rule is if something needs to happen before it is immediately dangerous then it is a C2.