Does an RCBO TD exist and can an RCD be used instead of Isolator

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Avo

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Hi,

As the title asks;

Do time delay rcbos exist?

And, I need an td rcd on the head end of my garage supply. In the small intermediate cu from the main 100a isolator is it allowable to install an rcd instead of another isolator? If not it means replacing the intermediate cu to gain 2 ways.

Finally, does the use of split load or rcbos in the garage cu change the methods of achieving discrimination?

Ta

Danny

 
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Hi mine in red.

Hi,As the title asks;

Do time delay rcbos exist? Not to my knowledge

And, I need an td rcd on the head end of my garage supply. In the small intermediate cu from the main 100a isolator is it allowable to install an rcd instead of another isolator? If not it means replacing the intermediate cu to gain 2 ways. Yes an RCD can be used as an isolator ( See BGB Pg 149 TABLE 53.4 )

Finally, does the use of split load or rcbos in the garage cu change the methods of achieving discrimination? Not sure what you are asking but YES discrimination WILL be achieved by use of an S type RCD UPSTREAM of any standard RCDs.Ta

Danny
 
Do time delay RCBO's exist..........sort of!

The only thing that I know is from Eaton in this case their part number MR100D. What is is is a clip on module that adds a 100mA, time delay RCD feature to an MCB this off their site:

MS2 100MA F FIT RCDPOD T DELAY

Product Ref.: MR100D

EAN: 5019586054388

RCBOs - Field Fittable Residual Current units

Any standard 1P or 1P+N Eaton MCB, 6 kA, 10 kA and 15 kA, can be field fitted with a residual current unit to create an RCBO.

For standard applications either the 230 - 240 Vac or 110 Vac ranges are used.

For applications where 110 V centre-tapped power supplies are provided, additional high levels of safety can be achieved through use of a standard Eaton 2P, type B or type C MCB fitted with a 110 CTE type residual current unit.

 
Avo,

Why do you need to RCD the supply end of this garage submain?

Is your supply TT?

If your supply is of the TN variety then you can get away without a RCD at the supply end if you're using SWA (which you've stated you are in your other thread)

 
Avo,Why do you need to RCD the supply end of this garage submain?

Is your supply TT?

If your supply is of the TN variety then you can get away without a RCD at the supply end if you're using SWA (which you've stated you are in your other thread)
Damn I just lost all my reply, damn iPad keyboard poop.

Simply put, although I was happy with 2 x t&e 2.5mm in conduit 2' underground feeding my workshop, I had too many tut tuts on here about it... I don't see why. Anyway, the workshop requires two protected rcd ways for my equipment. From what I understand the 2m of t&e where it enters the house does not need rcd protection because it's surface clipped, however it's debatable as to whether the conduit run is considered 'mechanically protected' so it's a grey area. So fitting an 30ma rcd would have been the best option. However that doesn't allow for discrimination (rcd in series) so the only option is an s type rcd. Though iirc, where a cable requires rcd protection a 30ma should be used, not a S type 100ma. I might have that wrong, so the alternative is to try and rip out the t&e and replace it with swa. I can then forget the rcd at the head end.

Because the current setup is two 2.5mm2 t&e giving a total CSA of 5mm2, to replace it with the same means going to 6mm2. Well actually 4mm2 would likely do, as I can forget grouping factor.

Just weighing up the pros/cons

 
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