just a quick one

[steptoe]

DP RCD'S are required on certain special installations IE caravan parks and jetty's they are made for the job. But as said I am unaware of a reg saying DP RCD protection is required on all TT installations. The regs do say that you do need to isolated all poles and phases and neutral on three phase though maybe this is were the confusion comes in.

perhaps,

:|

I no longer know anything.

:Blushing

 

[Chr!s]

Double pole isolation is required for a tt system.

Now your the designer, think will it be ok to disconnect the whole supply via your double pole incomer to carry out electrical work safely?

If not, steps is correct in a way because the regs require us to provide isolation of the live conductors in a tt for every circuit, so if you just turn of your rcbo/mcb you have not isolated the supply as your only isolating the line.

 

[wozz]

the way im reading this is the way Ive thought all along with regard to TT systems.

DP fault protection is not required, so MS and SP RCBOs are fine. Isolation wise DP should be provided and the MS does this. If you are working on a item of equipment DP isolation should be provided locally, declaring the breaker as the isolator for remote isolation (537.2.1.5) will not work as you only have SP isolation.

As for turning off the whole installation, i dont see much of a difference with in safety with turning off half the installation or all the installation if we are talking about domestic installation.

hence MS and SP rcbos are fine.

am i correct in thinking along these lines?

 

[la poste]

It's got nothing to do with DP fault isolation as DP RCBO's are readily available.

Where from?

I mean do you or anyone else have a recommendation for double pole RCBO's?

Where do you buy them from?

Not one supplier round here sells them over the counter.

If you ask for one you get looked at like you are talking a foreign language followed by "What the FK do you want one of those for?"

It's very odd.

I also enquired about double pole MCB's and was told there is absolutely no need for them over here, not available, the neutral is at 0 Volts and that is that.

 

[wozz]

electrifix sell DPrcbos, im sure all wholesalers could order them in just dont have them on the shelf or aware of the difference.

 

[Sidewinder]

Where from?I also enquired about double pole MCB's and was told there is absolutely no need for them over here, not available, the neutral is at 0 Volts and that is that.

What about when I am designing and building a control panel & I decide to use a 400V to 24V transformer for my control suppy.

It only runs off 2 phases, however, I have to put o/l proteciton in the primary & secondary, thus I must have 2 pole breakers.

Thus THEY ARE needed.

It seems your wholesalers are just not clued up.

Who is the electrician/engineer you or them?

Just give them :red card

 

[Andy™]

I also enquired about double pole MCB's and was told there is absolutely no need for them over here, not available, the neutral is at 0 Volts and that is that.

110v needs DP MCB's, since there is no neutral. as sidewinder says, give them :red card

 

[Sidewinder]

Andy,

Missed the 110V bit, but you could just substitute 110 for 24 in my post!!!

:Blushing :innocent

 

[steptoe]

sidewinder got sideswiped,

not often we get to witness that.

 

[Sidewinder]

Are you taking the proverbial Albert? ]

I do hope not!!! O)

 

[steptoe]

:innocent

:C

 

[Sidewinder]

:slap ]