Ring main.

[JKMRK1]

Question I have is, is it ok to have x2 ring main circuits on one 32amp type B MCB??

If so does this meet the current regs.

TIA.

 

[davesparks]

Is that any worse than a multi stranded 6mm or 10mm cable?

Always seems strange to me sparks dont bootlace these.

Yes it is different to a coarse stranded cable. Coarse stranded cables have the strands compacted tigether at manufacture and they are further compacted together by the termination. Multiple seperate conductors terminated together can, if not done properly, result in one conductor not being clamped at all.

Ferrules are only required for fine stranded cables as screw terminals can cut through the strands or spread them out so that good contact is not made.
Coarse stranded conductors don't suffer from these same issues if correctly terminated.

 

[Cbuk2k2]

Yes it is different to a coarse stranded cable. Coarse stranded cables have the strands compacted tigether at manufacture and they are further compacted together by the termination. Multiple seperate conductors terminated together can, if not done properly, result in one conductor not being clamped at all.

Ferrules are only required for fine stranded cables as screw terminals can cut through the strands or spread them out so that good contact is not made.
Coarse stranded conductors don't suffer from these same issues if correctly terminated.

Just looks strange to me where I’d almost always see some sort of crimp even on corse stranded cables.

 

[davesparks]

Just looks strange to me where I’d almost always see some sort of crimp even on corse stranded cables.

When/where would you always see some sort of crimp on coarse stranded?

 

[Cbuk2k2]

When/where would you always see some sort of crimp on coarse stranded?

Offshore oil and gas/petrochemical is where I work mainly.

Seems to be fairly standard practiceon the sites I’ve worked on.

 

[davesparks]

Offshore oil and gas/petrochemical is where I work mainly.

Seems to be fairly standard practiceon the sites I’ve worked on.

OK, so that's a specialised industry with its own rules and regulations, not really something you can compare to general installation work.

What type of crimps are used on coarse stranded cables? Are you talking about ferrules or something else?

 

[Cbuk2k2]

OK, so that's a specialised industry with its own rules and regulations, not really something you can compare to general installation work.

What type of crimps are used on coarse stranded cables? Are you talking about ferrules or something else?

We work to the same BS7671 rules as everyone else, I’m not aware it’s driven by any of the ATEX regulations etc. It’s just how I’ve always known it be done. Could be an American thing or a marine thing as there is a lot of crossover there.

Depends on the application but non insulated lugs and bootlace crimps are probably the most common.

 

[stevethesparks]

Will also be seen on all BMS panels

 

[davesparks]

It just seems weird to me that bootlace ferrules are being used on coarse stranded cables.

Post automatically merged: Aug 9, 2020

Will also be seen on all BMS panels

Any idea why?

 

[ChipFanDave]

Not seen it on gas production systems so not ATEX as far as I can see.

Also on all the lighting and power distribution panels for our BMS non of the SWA has ferrules on. The control cables obviously are.

 

[stevethesparks]

It just seems weird to me that bootlace ferrules are being used on coarse stranded cables.

Post automatically merged: Aug 9, 2020

Any idea why?

Not sure, at the time (approx 11-9 years ago) we were undertaking work for around 3 BMS firms, and all their panels had it, even the panels internal 13amp socket outlet.

 

[Ian1981]

It just seems weird to me that bootlace ferrules are being used on coarse stranded cables.

Post automatically merged: Aug 9, 2020

Any idea why?

Bootlace Ferrules on say 6 mm conductors seams to be the new YouTube electricians fad, one does it they all do it, spacing rcbo’s when the circuits are likely to be lightly loaded is another, monkey see monkey do.

 

[stevethesparks]

Not such a bad idea on screw terminals that are not quiet big enough for a folded 6mm, but not in cage clamp type terminals.

 

[Mike Johnson]

They do make the installation look neat, but I wished they had harmonised colours in the different sizes.

 

[Ian1981]

I don’t think it makes it look any neater, a bit of coloured plastic showing on the conductor, they are a necessity on fine stranded conductors but make no impression on me when used on standard coarse conductors, I just think why when connected to a circuit breaker inside a CU?

 

[Mike Johnson]

If the circuit breaker has a cage connector I agree, but not when putting a multi strand cable into a standard screw connector, can't guarantee the whole of the cable is connected securely the strands that are not under the screw are a potential ark point.