Motor installation:

[Tony S]

There was no animosity in starting this thread.

I’m used to European standards. Usually British, French, Benelux, Germany and Scandinavia. I’m retired now but still get asked about maters regarding motors and power distribution.
I was based in Britain but worked for a French company, our equipment came mainly from the above countries, so I’m a bit of a melting pot of ideas.

That picture was sent by a former colleague and is the first time I’ve seen a motor terminal box of that size without a fixed terminal block and I’ll admit I was shocked by it. My first concern is with vibration, it’s on steel decking so it will occur. A single screw terminal given the FLC of the motor? Normally it would be bolted compression lugs on to the terminal block.

At the end of the day it doesn’t matter if it passes AHJ inspection. Will “Our Man in Havana” sign it off and give the guarantee?

 

[iwire]

That picture was sent by a former colleague and is the first time I’ve seen a motor terminal box of that size without a fixed terminal block and I’ll admit I was shocked by it. My first concern is with vibration, it’s on steel decking so it will occur. A single screw terminal given the FLC of the motor?

Tens of, if not hundreds of thousands of installations just like that working fine.

Just not what you are used to.

At the end of the day it doesn’t matter if it passes AHJ inspection. Will “Our Man in Havana” sign it off and give the guarantee?

Well at the end of the day as an electrician here I don't care if your man signs off on it or not.

All that will matter to me is that I have followed the codes and job specifications I was obligated too.

If after the fact someone wants to apply different standards beyond what I was obligated to that is fine. That person can pay me to make whatever changes they want.

I have no idea how it works where you are but here engineers provided detailed job specifications going over everything from the quality of the devices we use, to the splicing methods, to the wire types we use and on and on.

Anything not directly spelled out in the jobs specifications will typically be installed to NEC minimums.

 

[mbrooke]

There was no animosity in starting this thread.

I’m used to European standards. Usually British, French, Benelux, Germany and Scandinavia. I’m retired now but still get asked about maters regarding motors and power distribution.
I was based in Britain but worked for a French company, our equipment came mainly from the above countries, so I’m a bit of a melting pot of ideas.

That picture was sent by a former colleague and is the first time I’ve seen a motor terminal box of that size without a fixed terminal block and I’ll admit I was shocked by it. My first concern is with vibration, it’s on steel decking so it will occur. A single screw terminal given the FLC of the motor? Normally it would be bolted compression lugs on to the terminal block.

At the end of the day it doesn’t matter if it passes AHJ inspection. Will “Our Man in Havana” sign it off and give the guarantee?

Do you have a picture of a typical UK motor termination of this size?

 

[iwire]

My concern here is the wire nuts look like they were put on with channel lock pliers, and as stated the wire might be to small per NEC though I doubt it would actually be dangerous in reality.

I use channel locks on those Ideal 454 nuts about half the time. They are big nuts holding larger conductors, I feel like getting them tight is a good thing.

Something is odd about the pictures and wire sizes.

For instance the picture of the blue wirenuts cannot be part of the supply to that 75 HP motor.

Those are ideal 454s, they might fit three 8 AWGs each but no way are they holding three greater than 2 AWG conductors.

Besides, what 75 HP motor circuit is going to have three wires under single splice? One feeder to two motor starters? I doubt it.

 

[iwire]

Wirenut specs http://www.idealind.com/media/pdfs/products/references/ideal_ul_listed_combinations.pdf


Around page 5

 

[ADub]

No bonding bushing?


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[mbrooke]

I use channel locks on those Ideal 454 nuts about half the time. They are big nuts holding larger conductors, I feel like getting them tight is a good thing.

Something is odd about the pictures and wire sizes.

For instance the picture of the blue wirenuts cannot be part of the supply to that 75 HP motor.

Those are ideal 454s, they might fit three 8 AWGs each but no way are they holding three greater than 2 AWG conductors.

Besides, what 75 HP motor circuit is going to have three wires under single splice? One feeder to two motor starters? I doubt it.

Good point, the circuit split makes me doubt that box is for the motor, as well as small wires.

 

[don_resqcapt19]

....
That picture was sent by a former colleague and is the first time I’ve seen a motor terminal box of that size without a fixed terminal block and I’ll admit I was shocked by it.

That is just a difference between here and there. I have never seen a motor over 2 or 3 hp with a fixed terminal block.

My first concern is with vibration, it’s on steel decking so it will occur. A single screw terminal given the FLC of the motor? Normally it would be bolted compression lugs on to the terminal block. ....

I am not really a fan of connectors, but that is just because I was taught and have always used compression terminals on the motor leads and the field leads and connected them together with bolts and nuts. Until recently the connection would have been insulated with rubber and plastic tape, but not I often use a Raychem "GelCap" for the insulation.

 

[Rolson]

Here is a peckerhead on a 500hp Siemens (European) motor with terminal kit. I usually only see these on European motors. But really wire nuts on a 75hp connection. I wouldn't install wire nuts on any motor over 10hp. Could rely on a bolt and taped which the motor probably had eyelits and were cut off. Also the burndy bibs or bits connection for fine strand works wonders on larger motor for a good connection and easy change out for bearing change outs or motor replacement.

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[kwired]

Here is a peckerhead on a 500hp Siemens (European) motor with terminal kit. I usually only see these on European motors. But really wire nuts on a 75hp connection. I wouldn't install wire nuts on any motor over 10hp. Could rely on a bolt and taped which the motor probably had eyelits and were cut off. Also the burndy bibs or bits connection for fine strand works wonders on larger motor for a good connection and easy change out for bearing change outs or motor replacement.

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Looks kind of opposite to what you would see in North America from an insulation perspective. Three totally exposed terminal bars instead of three well insulated terminations. Better hope the insulators that hold them in place don't break, or they will be shorting to the case or even phase to phase. Terminations used in N America sometimes do have insulation failures as well though.

 

[Rolson]

Yes, if the plastic breaker and that motor shorts I would not want to be anywhere near it. Even with a high interrupted rating on the circuit breaker there is still a vfd in the mix and a hard short on the drive usually does not end well.

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[Tony S]

Tony, I apologize for my ignorance:dunce::ashamed1:, but still curious. Under BS7671, what would be in violation?


My concern here is the wire nuts look like they were put on with channel lock pliers, and as stated the wire might be to small per NEC though I doubt it would actually be dangerous in reality.

Try looking at BS5733

 

[mbrooke]

Try looking at BS5733

Thanks

Any section or rule in particular?

 

[Tony S]

Start on page one and then use the index.

 

[peter d]

I used to work for a machine tool builder and we used crimp on ring terminals, nuts and bolts, and tape to make our motor connections. I tried to turn them on to Porlaris connectors but they didn't want to hear about it. :roll: Suffice it to say, I didn't last long working there.