Joining 4 x 10mm conductors?

[HappyHippyDad]

This is a follow on to my kiln thread.

The kiln is 3 phase but can be run on single phase. It is 12kW.

It has 5 core 10mm2 flex attached to it.

The colours are brown, blue, grey, black, green/yellow.

I'm just looking for the best way to attach L1, L2, L3 and the single phase 10mm conductor together?

A 60A junction box wouldn't be suitable as there are too many conductors to squeeze in. I was thinking of some kind of terminal block with separate holes for each conductor (exactly like an earthing block, but insulated) but I can't find any? This would then be in a small enclosure/adaptable box etc.

I've got a feeling this is something pretty straight forward, but I've never had to join 4 x 10mm before, so it's not on my radar.

Also, with the 3 phase colours above. Are they UK (new) colours, meaning that the blue is the neutral? Below is a picture of the actual cable. the whitish looking one is actually grey. Cheers ?

 

[pc1966]

There may be many more, but something like this might do:

0 048 52 | Legrand Distribution Block, 8 Way, 1.5 → 16mm², 80A, 400 V ac, Black | RS

uk.rs-online.com

 

[pc1966]

Looks like they do a 4-way as well which would better suit you:

0 048 50 | Legrand Distribution Block, 4 Way, 1.5 → 16mm², 80A, 400 V ac, Black | RS

uk.rs-online.com

 

[HappyHippyDad]

Looks like they do a 4-way as well which would better suit you:

0 048 50 | Legrand Distribution Block, 4 Way, 1.5 → 16mm², 80A, 400 V ac, Black | RS

uk.rs-online.com

Looks good! Din rail mount too! Thanks PC ?

With regards the colours of the cable... Are they definitely UK (new colours) meaning the neutral is the blue? I am unsure due to the fact I dont deal with 3 phase, but also the fact that this is an old wenger kiln which was built way before 2006 when the colours changed.

 

[telectrix]

i would assume Bn/Bk/Gy to be L1,L2,L3, and the blue to be N. if the kiln is wired in star, L1 -N, L2 - N, L3 -N, should give 3 equal readings on continuity.

 

[Lucien Nunes]

ome kind of terminal block with separate holes for each conductor (exactly like an earthing block, but insulated) but I can't find any?

There are many different kinds, I keep half a dozen flavours in stock and used three only this morning. The type PC1966 linked are good, then you have the totally enclosed 'Italian' type that I use the most, e.g.

Cembre 5x16mm commoning block

Possibly the most substantial method is to put the requisite number of DIN rail terminals on a rail and link them with a commoning bar. Finally you can do worse than a stack of ring terminals on an insulated rail-mounted stud.

Yes those are harmonised colours. Check the wiring at the kiln end in case someone has done something daft. Be prepared to re-terminate that end if needed.

 

[pc1966]

I'm sure I have seen the Cembre block somewhere, though this seems to be RS "own brand" but probably the same:

RS PRO Commoning Block, 4 Way, 450 V | RS

uk.rs-online.com

Might be a better choice (cheaper per block!) but not in stock until 1st March it seems.

 

[Lucien Nunes]

I've just looked at the pic on a bigger screen.... is that SY cable really 10mm²? It looks more like 4.0 or 6.0. It might just be the perspective of the pic though. And, why would anyone have fitted 5-core 10mm² when the current on 3-phase would only be 18 amps?

Also, are you are mounting an isolator nearby? Perhaps that would have some influence on how the cable is terminated and/or whether it is simply better to replace the existing.

Anyway, here are some more commoning blocks.

This first one is out of stock at the mo but I keep these in my toolbox as problem solvers for when a Wago isn't big enough. The RS Pro range includes some useful sizes, I find a lot of applications for the one with one 16mm² and ten 6mm² entries
4-way 16mm² commoning block from RS

If you want to go large, these Weidmüller blocks are well engineered and have both DIN rail and screw-hole mounting.
Weidmüller 5-way block

etc...

Ha - cross posted the same product as @pc1966. I use tons of these, they are fine. Made to a price - plain brass with pinch screws rather than rising cage clamps but substantial and robust, I've never sheared one or cracked the housing.

 

[HappyHippyDad]

I've just looked at the pic on a bigger screen.... is that SY cable really 10mm²? It looks more like 4.0 or 6.0. It might just be the perspective of the pic though. And, why would anyone have fitted 5-core 10mm² when the current on 3-phase would only be 18 amps?

Also, are you are mounting an isolator nearby? Perhaps that would have some influence on how the cable is terminated and/or whether it is simply better to replace the existing.

Anyway, here are some more commoning blocks.

This first one is out of stock at the mo but I keep these in my toolbox as problem solvers for when a Wago isn't big enough. The RS Pro range includes some useful sizes, I find a lot of applications for the one with one 16mm² and ten 6mm² entries
4-way 16mm² commoning block from RS

If you want to go large, these Weidmüller blocks are well engineered and have both DIN rail and screw-hole mounting.
Weidmüller 5-way block

etc...

Ha - cross posted the same product as @pc1966. I use tons of these, they are fine. Made to a price - plain brass with pinch screws rather than rising cage clamps but substantial and robust, I've never sheared one or cracked the housing.

I have to admit I have just assumed it's 10mm from looking at it. I'll get a pair of callipers on it to make sure but I'd be very surprised if it was 6mm.

The specification plate does state 415V or 240V, so would they have used a cable that could accommodate both? Is this likely?

How embarrassing, I didn't notice it was SY. I shall make sure to add the gland to the quote!

I was planning on using a 60A rotary switch as an isolator.

 

[Lucien Nunes]

Sure, I'm not saying it isn't 10mm², I just thought it looked smaller based on recognisable items like the screw in the door handle

As you say, the kiln predates the harmonised colours and was probably supplied without cable. Commercial installations would often have had singles in flexible metal conduit or similar, rather than flex. Therefore there's no reason to assume that the present piece of SY is the ideal thing for the job, it might be what the previous installer had in his van.

 

[loz2754]

The SY cable may well be sized correctly for 3 phase but would need to be bigger obviously for single phase as the neutral will be carrying the full current. Did someone already mention this? I'm going a bit senile.....

 

[Lucien Nunes]

Yes. There was a previous thread about calculating the load, which could have gone like:
'12000/230=52 and 52/3=17.4, check that each element bank is somewhat below 230/17.4=13.5Ω, if so kiln is indeed 12kW as suspected, supply current on single phase is 52A, job done' but rambled on a bit. Somewhere along the way the point surfaced a few times.

 

[ipf]

I find, with SY cable, the size can be surprising. 4mm can look like 2.5, 6.0mm like 4, etc.

Could be because it's flexible.......and not manufactured to any British or European standard, as far as I know.
Isn't it intended as a control cable?.... although 10mm 4c, with such colours as control only, it seems like supply cable. You'd think it would be the all black, numbered cores as controls.
Different manufacturers, different specs, maybe?

 

[Mike Johnson]

Or use one on these from RS Components, I have a couple spare if you want one?

Legrand, 4 Pole Interface Module, DIN Rail Mount​

Can't get the link to work, but go to there web site and look for the above, they are a very neat three phase enclosed connector.

 

[Mike Johnson]

Try again: 0 048 84 | Legrand, 4 Pole Interface Module, DIN Rail Mount | RS Components -

 

[DPG]

Or use one on these from RS Components, I have a couple spare if you want one?

Legrand, 4 Pole Interface Module, DIN Rail Mount​

Can't get the link to work, but go to there web site and look for the above, they are a very neat three phase enclosed connector.

They look nice.

 

[Mike Johnson]

They also manufacture a bigger unit, ideal for a three phase board: 0 048 88 | Legrand, 15 Pole Interface Module, DIN Rail Mount | RS Components - https://uk.rs-online.com/web/p/interface-modules/6203665/

And lots of others: Interface Modules | Passive & Relay Modules | RS Components - https://uk.rs-online.com/web/c/connectors/terminal-blocks/interface-modules/

 

[Lucien Nunes]

Although in this case only 2 pole needed, as it's going onto a single phase supply.

 

[Mike Johnson]

Agreed, but there are plenty of others on the site I posted the link too that will accommodate that.

 

[Vortigern]

Usually on dual types of supply like that i.e. three phase/single phase, there is a plate inside the equipment that lets you configure the wiring for single phase supply or three phase, so that you get a two core and earth supply and reconfigure the links inside the appliance rather than try to link one single phase wire to the five core cable. So at your switch you would have a cable coming out from say a rotary isolator straight to the appliance. From there you would have a cable that would go directly to the links. Configuring the links is key to this. Or...three phase rotary isolator and the five core goes into that with a link to each of the L1-L2-L3 at the supply side. I suspect you need to link at where that five core goes to and inspect the arrangement. I have been caught out by this before by assuming the links were configured for three phase and they weren't. So you would need to see how the links are configured and be sure you are linking in properly.

 

[Vortigern]

The thing about kilns is they are very demanding current wise in the sense that they draw full current for hours at a time while getting up to temperature so the supply cable must really be adequate for this. While you would be getting circa 20a per phase on three phase you would notionally be drawing 52 amps on a single phase. The last kiln I put in it seemed by calculation I should use 6mm for a 35a load. I went up to 10mm as the manufacturer recommended that size.

 

[pc1966]

Yes, on reflection I would be replacing the flexible lead and having L1-L2-L3 linked in the kiln, instead of joining cores (unless it really is 10mm already).

What I wonder is the choice of cable. H07RN-F is usually 60C max which seems low for an oven/kiln, even if it is far from the heated section as I expect it gets pretty warm inside!

6242B is avaiable to 10mm and rated to 90C but not that flexible, so if it is fairly static like a cooker then maybe that would be acceptable?

I know you can get silicone rubber flex but personally never seen it above about 2.5mm which ain't going to do 52A.

 

[Mike Johnson]

I don't know anything about Kilns, but should not the heat be inside, so the cable should not see that type of temperature?

Just a thought.

 

[pc1966]

Sure it won't be the 400C or whatever is inside! But I imagine it is going to be warm still. Maybe there is something on the specs or drawing to indicate what rating of cable is needed?

 

[HappyHippyDad]

Sure it won't be the 400C or whatever is inside! But I imagine it is going to be warm still. Maybe there is something on the specs or drawing to indicate what rating of cable is needed?

1800°C... pretty hot!

 

[HappyHippyDad]

Usually on dual types of supply like that i.e. three phase/single phase, there is a plate inside the equipment that lets you configure the wiring for single phase supply or three phase, so that you get a two core and earth supply and reconfigure the links inside the appliance rather than try to link one single phase wire to the five core cable. So at your switch you would have a cable coming out from say a rotary isolator straight to the appliance. From there you would have a cable that would go directly to the links. Configuring the links is key to this. Or...three phase rotary isolator and the five core goes into that with a link to each of the L1-L2-L3 at the supply side. I suspect you need to link at where that five core goes to and inspect the arrangement. I have been caught out by this before by assuming the links were configured for three phase and they weren't. So you would need to see how the links are configured and be sure you are linking in properly.

Thanks Vortigern. I'm guessing this plate would have be located on the 4 way connector block in the picture below? is this something that is usually removeable (i.e able to be lost), or attached to the block permanently?



Now my next question is going to be is there some kind of 60A + copper link available? Just like you have in cookers sometimes. This will be much neater than a separate junction box joining the 5 core cable to 3 core.

 

[Dave OCD]

If you're using a 60 amp rotary isolator HHD you could quite possibly connect the flex as you normally would on the outgoing side to L1,L2,L3 and N but link out L1,L2 and L3 on the incoming supply side. Although even at 60 amp rating those isolators aren't exactly roomy inside.

 

[HappyHippyDad]

If you're using a 60 amp rotary isolator HHD you could quite possibly connect the flex as you normally would on the outgoing side to L1,L2,L3 and N but link out L1,L2 and L3 on the incoming supply side. Although even at 60 amp rating those isolators aren't exactly roomy inside.

Now that's an idea ?
Thanks Dave.

 

[Vortigern]

Now that's an idea

Yeh he pinched from my script earlier

 

[Vortigern]

Actually it would be good to see that plate in picture form on the kiln. I think you need to change the 5 core cable to 2 core and earth 10mm or 16mm (??) to be totally safe. You might find that the plate/link is already on there and just has to be moved. The cable on the kiln is 90c cable flexible. So if you bought that it would be quite expensive to be sure. There must be a lot of heat radiated as the kiln manufacturer said you must have 18 in space all around the kiln so no wonder 90c cable. The rotary isolator is a Scame and plenty of room to do whatever you decide inside it.

 

[HappyHippyDad]

Yeh he pinched from my script earlier

I've just re-read yours more thoroughly. You did indeed mention that! Thankyou ?

 

[Lucien Nunes]

If there are links they will probably be ordinary flat bits of brass with two holes, like the links in a motor terminal box. You could make your own.

Thinking about the cable and my earlier comment about flexible conduit, I would probably still do it that way. Galvanised flexible with tri-rated singles, rated to 105 deg.C but also resistant to burns if something hot touches the exterior.

 

[Dave OCD]

Yeh he pinched from my script earlier

I honestly didn't read your post mate, thought I was having a good idea. ?

 

[Vortigern]

That's perfectly ok @Dave OCD, just thought I would get my patent in before you got all the kudos, petty jealousy I am sorry to say. I guessed you hadn't read my post and why would anyone anyway, boring! I know I do witter on a bit sometimes.