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CA-ON Multi-conductor wire

Ontario
Type
Product
trlvn

trlvn

Ultra Member
Hi:

So, a member hooked me up with a reversing drum switch that I want to add to my Craftex mill-drill. I'm not an electrician but I believe I understand the necessary wiring...I just need a short piece of cable with at least 5 conductors plus ground to go between the switch and motor junction box. I'm not sure where to get this wire and I'd like to be clear exactly what is needed.

The piece required is short: as little as 1 foot would likely be enough but a 2 foot piece would make it easier to install.

The motor draws 220V @ 12 amps. For this short a run, I believe 16 gauge is sufficient. Is that right?

Armoured cable isn't necessary since this is up and away from the spindle, I think. The existing connection between the mag switch and the junction box is not armoured.

In the past, I've found electrical supply places to be distinctly unhelpful. If you don't know precisely what is needed, they don't want to offer any advice since that might make them liable if something goes wrong. Any suggestions on outlets that are more DIY-friendly in the GTA?

Craig
(I think this topic may have be discussed before I couldn't come up with the right search terms.)
 
Can you post a picture of the wiring in the motor junction box before we look at getting wire? We need to see how easy it will be wire the motor. you should use #14 gauge wire or larger and make sure the wire is rated for 250vac or higher. You can
Bare min use 3 motor conductors and a bond to ground so you could use 4 conductor #14 sjoow. Better method is the 5 wire with bond so a 6 conductor #14 sjoow.
Couple vids to help.
 
I would take a length of flexible conduit (liquid tight, armoured, or similar) and pass individual stranded wires, often called “pull wires” at the supplier. You can buy both at Home Depot. The wires will be in little spools in different colours or you can get them to sell you it off the big spools.
Won’t be much more than at the suppliers and you don’t have to deal with them.
 
BldrJ said:
I would take a length of flexible conduit (liquid tight, armoured, or similar) and pass individual stranded wires, often called “pull wires” at the supplier. You can buy both at Home Depot. The wires will be in little spools in different colours or you can get them to sell you it off the big spools.
Won’t be much more than at the suppliers and you don’t have to deal with them.
Click to expand...
This likely a better way to do it. Early morning I was stuck on the cable. Should be someone local can give him the wire.
 
You don't need any more conductors than the motor has in its junction box. You are just extending them. As @djberta suggests, you might need less. Anytime that you permanently join two supply wires at the motor, that's one more wire than you needed in the cable. I'd figure that out before you get wire.

Important - don't get solid wire. Get stranded flexible wire.

I'd get 14 gauge but 12 is still small and won't hurt.

If you want cable instead of pulls in conduit, Digi-Key has a gazzilion options and usually sells by the foot. If you call them on the phone, they are very helpful - not at all like the big box stores.
 
+1 on Digikey and making sure you have an adequate voltage rating on the cable.

Digikey was the best price for multi conductor, voltage (600?) rated cable when I was gearing up my drill press mod. Fast and cheep shipping too. If I recall, the cable was rated for the German railway standard.

Oh, and the conductors were numbered for easy ID.

D :cool:
 
Last edited:
@Susquatch Thanks for the Digi-Key suggestion (even if they are a US company). After a bit of filtering, the following looks promising:


Re the wire gauge, the wiring has to pass through a 1/2" pipe thread opening so, with strain relief, the max cable diameter is a hair over 3/8". Given the extremely short run, there will be minimal resistance from the wire so I think 16 gauge is sufficient. The 2 meter power lead is 14 gauge.

Also, space in the junction box is extremely limited. The wires from the existing mag switch enter at right. Note that the overload protection (red button) is also in this box (connects via the tan wires).

B1977 motor junction box.jpg


Craig
 
djberta said:
Bare min use 3 motor conductors and a bond to ground so you could use 4 conductor #14 sjoow
Click to expand...
I have basing my plan off the second video you linked to. (A screen capture is printed out and sitting beside me!) I can follow the 5 conductor scheme but I didn't understand the 3 conductor version. I'll go back and view that section again.

Craig
 
trlvn said:
@Susquatch Thanks for the Digi-Key suggestion (even if they are a US company). After a bit of filtering, the following looks promising:


Craig
Click to expand...

Craig

The cable I ordered from Digikey for my drill press was another Lapp product, it has a rubber ("thermoplastic polymer") jacket and is less expensive at $3.58/ft. Digikey P/N 2320-221605-DS-ND for 5 conductors 16 AWG. It's 600V rated. In Digikey's numbering change the "5" for your required number of conductors if you need different.

Digikey Link

IMHO I'd lean that way because the jacket would be more robust - I'm thinking about where it gets clamped entering junction boxes.

Unfortunately it is an American product from an American company.....but I think that's what you'd find at Home Depot etc. too.

D :cool:
 
trlvn said:
Given the extremely short run, there will be minimal resistance from the wire so I think 16 gauge is sufficient. The 2 meter power lead is 14 gauge.
Click to expand...

I think you are thinking about the affect of total resistance on the motor - ie voltage drop at max current. While that is important, you also need to be thinking in terms of the resistance per unit of wire length. This is what causes a wire to get hot and melt or fuse. Since the power calculation is done at rated load, it looks like a smaller wire would be fine. And maybe it is. But you also need to take in-rush current into account and what that can do to a wire and especially its connections. Since a bigger wire is peanuts in terms of $, and bigger is always better, but smaller is always worse, I always prefer to upsize. My personal rule of thumb for most motor wiring is one or two gauges bigger (smaller number) than required.
 
Susquatch said:
I think you are thinking about the affect of total resistance on the motor - ie voltage drop at max current. While that is important, you also need to be thinking in terms of the resistance per unit of wire length. This is what causes a wire to get hot and melt or fuse. Since the power calculation is done at rated load, it looks like a smaller wire would be fine. And maybe it is. But you also need to take in-rush current into account and what that can do to a wire and especially its connections. Since a bigger wire is peanuts in terms of $, and bigger is always better, but smaller is always worse, I always prefer to upsize. My personal rule of thumb for most motor wiring is one or two gauges bigger (smaller number) than required.
Click to expand...

Normally I'd agree about bigger being better but in this case the maximum diameter is also a concern. It would be difficult to modify the drum switch but I'd have to replace the motor junction box. There is no space to enlarge the entrance for the cable. I don't want to get into trying to find and mount a replacement box.

Junction box.jpg


Illegible, I know, but the box is 3.5 X 3 inches.

Craig
 
from memory the 16ga cable is iirc about 3/8 but will take a look agian when i go back down EDIT* nevermind datasheet to the rescue

8.9mm outer diameter
 
trlvn said:
Re the wire gauge, the wiring has to pass through a 1/2" pipe thread opening so, with strain relief, the max cable diameter is a hair over 3/8".
Click to expand...

I forgot to comment on this.

Can you open the existing entry a bit to accept a larger clamp?

Can you expand the size of the terminal box so things are not so cramped?

And lastly, do you really need so many conductors?

trlvn said:
Given the extremely short run, there will be minimal resistance from the wire so I think 16 gauge is sufficient. The 2 meter power lead is 14 gauge.
Click to expand...

If the power lead was 14, then the motor leads should be at least that big too. As I mentioned earlier, length is really only a factor when considering voltage drop. It doesn't play much of a role in limiting the load on the wire itself and the connections. Look at it this way. Fuses are typically VERY short. But they still burn out.
 
Susquatch said:
And lastly, do you really need so many conductors?
Click to expand...
Thanks for reminding me. The video I watched showed two wiring schemes. One with 5 conductors and the other with just 3. I can follow the 5 conductor scheme but the 3 conductor arrangement seems like magic. It is kind of tagged on at the end of the video. He draws the current path for forward and reverse so maybe if I study that more closely I'll finally grok how it works with only 3 leads to the motor.

Craig
 
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