connecting 4 SQ mm wires

[h90]

We rearrange 2 CNC machines and they cut the wires.

Wires are 4 square mm, not the solid one, these made of strands.

so one cable comes from the fuse box and will be split into 2 cables. One for each machine.

I thought of first buying some connectors and than cut the existing wiring, but no last thing in the evening they cut it and want to twist the wires together.

What can I get fast tomorrow morning (HomePro, HomeWorks, etc) to connect the cut wires so we can work?

Theoretically they machines should be connected for 26kW (in real life it will be a fraction of it). But still not something I want to see twisted wires.

[bankruatsteve]

Don't worry. Thais "twist and tape" to perfection. It's not likely you will find a connector for 4mm2 easily anyway - or one that connects better than twist and tape.

[h90]

would be soldering together of the wires be a suitable solution?

[RichCor]

It really depends on what the total current being pulled on the 4mm² wired circuit.

I would use a coupling connectors, and might even be tempted to use a "Safety Breaker" as the coupling connector as it has some really nice screw down connection points (though it really depends on where the cut/break was made and where the new coupling can be positioned. Either way, the connection should be made INSIDE A BOX.

Make sure you have enough existing undamaged wire to complete the run, or use new cable from the coupling.

[sandyf]

would be soldering together of the wires be a suitable solution?

Probably the best solution but not that easy.

The largest size of terminal strip, often referred to as 'Chocolate Block' is the most straightforward solution and will handle 4 sq mm quite easily.

You must be talking 3 phase here, you couldn't possibly run anything like 26Kw on 4 sq mm. The phases need to be reconnected in the right order or you may get movement in the wrong direction when you start up.

[Gonsalviz]

Don't know where you are but there are shops that have such crimping equipment. PEA/MEA would be a start. If they can't do it, they should know where to send you. They have contractors for such things.

[Gonsalviz]

Sorry about the double post.

Edited September 10, 2015 by Gonsalviz

[Crossy]

Lots of solutions that are not twist-n-tape. Large choc-bloc (a ceramic one would be best at the sort of currents you're talking), butt-crimps and heatshrink, ring-crimps and a bolt again with heatshrink.

As above, put it in a box to protect.

Personally, I'd use a small distribution board and give each machine it's own breaker, not cheap but neat, safe and professional looking.

26kW is around 40A per phase, rather near the line for 4mm² anyway, perhaps running a 10mm² sub-main to the above new distribution board would be the best way to go.

[h90]

would be soldering together of the wires be a suitable solution?

Probably the best solution but not that easy.

The largest size of terminal strip, often referred to as 'Chocolate Block' is the most straightforward solution and will handle 4 sq mm quite easily.

You must be talking 3 phase here, you couldn't possibly run anything like 26Kw on 4 sq mm. The phases need to be reconnected in the right order or you may get movement in the wrong direction when you start up.

the 26 KW are out of the machine descriptions and added for every device. I would doubt that in real life even half of it would happen. Actually from the stronger machine I never saw the power meter of the main spindle ever going higher than 5%. And I doubt the 4KW electric motor for the suction unit really uses full 4KW.....it is just his maximum.

Can you give me a pic of the chocolate block.....I tried to put it in google but got only the pictures you would expect searching for chocolate

Yes I know about the movements.....

[h90]

Lots of solutions that are not twist-n-tape. Large choc-bloc (a ceramic one would be best at the sort of currents you're talking), butt-crimps and heatshrink, ring-crimps and a bolt again with heatshrink.

As above, put it in a box to protect.

Personally, I'd use a small distribution board and give each machine it's own breaker, not cheap but neat, safe and professional looking.

26kW is around 40A per phase, rather near the line for 4mm² anyway, perhaps running a 10mm² sub-main to the above new distribution board would be the best way to go.

the 26KW is just what I added from the machine description. It worked before with 4mm2 without problems. I think it is much less in reality, but I can only follow the machine descriptions.

Will have to check what I can find at homepro...

thanks

h90

[Crossy]

Will have to check what I can find at homepro...

If you have a dedicated electrical shop rather than HomePro you may score something more suitable as you are looking to join wiring that is larger than that normally found in homes.

Are the cables in question flexible (many strands or just a few)?

I would avoid using solder unless you are practised and have the correct kit, it's very easy to get a dry joint which will do all sorts of nasty things when you get current flowing.

[sandyf]

would be soldering together of the wires be a suitable solution?

Probably the best solution but not that easy.

The largest size of terminal strip, often referred to as 'Chocolate Block' is the most straightforward solution and will handle 4 sq mm quite easily.

You must be talking 3 phase here, you couldn't possibly run anything like 26Kw on 4 sq mm. The phases need to be reconnected in the right order or you may get movement in the wrong direction when you start up.

the 26 KW are out of the machine descriptions and added for every device. I would doubt that in real life even half of it would happen. Actually from the stronger machine I never saw the power meter of the main spindle ever going higher than 5%. And I doubt the 4KW electric motor for the suction unit really uses full 4KW.....it is just his maximum.

Can you give me a pic of the chocolate block.....I tried to put it in google but got only the pictures you would expect searching for chocolate

Yes I know about the movements.....

This is the type of connector I was referring to.

The 26 KW will be the total load across the phases, approx 9Kw per phase. I am surprised that it is not quoted in KVA as the bulk of the load will be inductive from the motors.

What kind of machine is it, I worked in metal fabrication and plastic factories for many years. Plastic machines have a high resistive load from the heating elements.

You are quite right that the operating current will be a lot less than indicated by the full load, unlikely that the motors would come under full load conditions, but it has to be catered for.

Another factor that comes into play is the motor configuration. 3 phase motors are often delta configuration which means the load is across 415v and draws a lot less current.

[sandyf]

Will have to check what I can find at homepro...

If you have a dedicated electrical shop rather than HomePro you may score something more suitable as you are looking to join wiring that is larger than that normally found in homes.

Are the cables in question flexible (many strands or just a few)?

I would avoid using solder unless you are practised and have the correct kit, it's very easy to get a dry joint which will do all sorts of nasty things when you get current flowing.

Agreed & agreed. Homepro is DIY, you need an industrial outlet. Multi core is quite tricky to solder and not for the inexperienced.

[h90]

Will have to check what I can find at homepro...

If you have a dedicated electrical shop rather than HomePro you may score something more suitable as you are looking to join wiring that is larger than that normally found in homes.

Are the cables in question flexible (many strands or just a few)?

I would avoid using solder unless you are practised and have the correct kit, it's very easy to get a dry joint which will do all sorts of nasty things when you get current flowing.

I am good enough in soldering, that's not the problem....but my kit is for electronic so I need a bit bigger iron. And I am scared about corrosion, had one copper wire (for speaker) that dissolved into powder 1 year after soldering.....

But my guys found some clamp thing that looks good......

Edit: many strands, flexible.

Edited September 11, 2015 by h90

[h90]

would be soldering together of the wires be a suitable solution?

Probably the best solution but not that easy.

The largest size of terminal strip, often referred to as 'Chocolate Block' is the most straightforward solution and will handle 4 sq mm quite easily.

You must be talking 3 phase here, you couldn't possibly run anything like 26Kw on 4 sq mm. The phases need to be reconnected in the right order or you may get movement in the wrong direction when you start up.

the 26 KW are out of the machine descriptions and added for every device. I would doubt that in real life even half of it would happen. Actually from the stronger machine I never saw the power meter of the main spindle ever going higher than 5%. And I doubt the 4KW electric motor for the suction unit really uses full 4KW.....it is just his maximum.

Can you give me a pic of the chocolate block.....I tried to put it in google but got only the pictures you would expect searching for chocolate

Yes I know about the movements.....

This is the type of connector I was referring to.

The 26 KW will be the total load across the phases, approx 9Kw per phase. I am surprised that it is not quoted in KVA as the bulk of the load will be inductive from the motors.

What kind of machine is it, I worked in metal fabrication and plastic factories for many years. Plastic machines have a high resistive load from the heating elements.

You are quite right that the operating current will be a lot less than indicated by the full load, unlikely that the motors would come under full load conditions, but it has to be catered for.

Another factor that comes into play is the motor configuration. 3 phase motors are often delta configuration which means the load is across 415v and draws a lot less current.

One is a EMCO CNC lathe with Sinumeric 810D. I am not sure, it may even push electric back into the net when it brakes. It has a hydraulic included (normal 3 phase) and a suction unit with 4 kw.

Writting Imax=33 Amp for the Emco without suction.

Other is a Economos lathe Sinumeric 810T, rated at 8.5 kW inculding suction.

Both are mainly used to rubber (NBR, EPDM), Polyurethane cutting to produce hydraulic seals. So basically the runs with almost zero torque. But needs all the time spin up and brake. Won't need too much power. But the suctions are use a lot (the chip/ribbon of these plastics are nasty and must be sucked away and cut in small pieces, before they mess up everything).

So if everyone need hydraulic/pneumatic seals I give away some for free for all the help the community here gave me already .

My guys found some strange clamps, already so the problem is fixed....they aren't very pretty but will do the job....better than the twisting....

Thanks everyone!

[Crossy]

Glad the chaps found something suitable

Although now a moot point, the soldering of flexible cable is an issue, the solder tends to wick up under the insulation and creates a hidden stress point which can fracture an lead to arcing.

Generally crimping is the way to go on any power wiring all the way to the UHV super-grid systems.

[h90]

Glad the chaps found something suitable

Although now a moot point, the soldering of flexible cable is an issue, the solder tends to wick up under the insulation and creates a hidden stress point which can fracture an lead to arcing.

Generally crimping is the way to go on any power wiring all the way to the UHV super-grid systems.

It has a plastic housing.....

I am thinking if I should take the torch and try on the edge if it is some cheap plastic that burns easily, or if I should just smile silly and be happy with it......

[sandyf]

Glad the chaps found something suitable

Although now a moot point, the soldering of flexible cable is an issue, the solder tends to wick up under the insulation and creates a hidden stress point which can fracture an lead to arcing.

Generally crimping is the way to go on any power wiring all the way to the UHV super-grid systems.

Back in the 60's all aircraft wiring was multicore and all joints soldered. We had to use fairly thick sleeving to support the joint. Replacing a 48 pin plug was a nightmare.

[Crossy]

Glad the chaps found something suitable

Although now a moot point, the soldering of flexible cable is an issue, the solder tends to wick up under the insulation and creates a hidden stress point which can fracture an lead to arcing.

Generally crimping is the way to go on any power wiring all the way to the UHV super-grid systems.

Back in the 60's all aircraft wiring was multicore and all joints soldered. We had to use fairly thick sleeving to support the joint. Replacing a 48 pin plug was a nightmare.

Yup, we had the same issue with military ship systems, every joint had Hellerman sleeves to insulate and provide vibration support. Spent an inordinately long time learning how to solder without burning the insulation, how to correctly apply the sleeves and how to neatly lace up the harness. Look at the same systems now and all cable joints and connector terminals are machine crimped.

[h90]

Glad the chaps found something suitable

Although now a moot point, the soldering of flexible cable is an issue, the solder tends to wick up under the insulation and creates a hidden stress point which can fracture an lead to arcing.

Generally crimping is the way to go on any power wiring all the way to the UHV super-grid systems.

Back in the 60's all aircraft wiring was multicore and all joints soldered. We had to use fairly thick sleeving to support the joint. Replacing a 48 pin plug was a nightmare.

yeah.....I had to do a similar one once, a kind of non standard serial port for an ancient machine, but I removed the sleeves. Still you solder one joint you unsolder the nearby joint, because it is deep inside the connector, you have everything together, you messed so much with the small wires, that one wire in the middle brakes off.

you need to be good at soldering + have the patience of a Buddhist monk.......But at least it wasn't an airplane, if a joint is loose you get an error, but don't fall from the sky....

[sandyf]

Glad the chaps found something suitable

Although now a moot point, the soldering of flexible cable is an issue, the solder tends to wick up under the insulation and creates a hidden stress point which can fracture an lead to arcing.

Generally crimping is the way to go on any power wiring all the way to the UHV super-grid systems.

Back in the 60's all aircraft wiring was multicore and all joints soldered. We had to use fairly thick sleeving to support the joint. Replacing a 48 pin plug was a nightmare.

Yup, we had the same issue with military ship systems, every joint had Hellerman sleeves to insulate and provide vibration support. Spent an inordinately long time learning how to solder without burning the insulation, how to correctly apply the sleeves and how to neatly lace up the harness. Look at the same systems now and all cable joints and connector terminals are machine crimped.

I should imagine most of the military electrical materials came from the same source, in my day it was all Plessey plugs and sockets. There wasn't much change before I came out in 77.

Once acquired the skill seems to remain, Went for a job in the late 80's installing ATM's and we had to do a simple soldering test, guy thought I worked for BT. Didn't get the job, had turned 40 and they said I was too old, German company.

[Crossy]

The really scary thing is that most of the kit I worked on is now in the Royal Navy Museum

And you are correct, you never forget the skill although I'd have a hard time doing any lacing these days. I get problems from my contractors here as I'm insisting on military quality documentation.

[sandyf]

The really scary thing is that most of the kit I worked on is now in the Royal Navy Museum

And you are correct, you never forget the skill although I'd have a hard time doing any lacing these days. I get problems from my contractors here as I'm insisting on military quality documentation.

Tell me about it. I spent most of my service on Buccaneers, inherited from the RN when past their sell by date. When I was at Honington it became home to 809 sqdn and I had some RN guys under me in the instrument bay.