Old Drill Press electrical help for DIYer, replacing cord caused short in outlet

[adamadamadam01]

Hello all! So as the title says and as the pictures will demonstrate, I have received a very old drill press. However, the cord was absolutely destroyed and needed to be replaced. I had no experience doing this, but followed along with YT videos and was able to replace all the wires, and added a ground wire as well. However, when I plugged it into my outlet, which I later found out was a GFCI outlet, it caused the outlet to short. My friend and I suspect that the primary reason that this happened was because the surface for the ground wire was not very good, as there was still old paint covering up some of the metal. I was also told that the GFCI outlet could be the issue, but I wanted to make sure that the wiring of the motor looks good before I attempt to plug anything in again. I was told later on told to use a multimeter to test the ground wire, and I was able to get 0 ohms from it, but this was after I filed away all the paint and made sure bare metal was the exposed. I am hoping that those with a better sense for this than me can help me with this diagnosis of what could have gone wrong. I can attach more information and photos as needed, but I am attaching photos of the surface for the ground wire before and after I was able to file away the old paint.

 

[adamadamadam01]

I will attach a few other pictures of inside the drill press motor as well, in case they help anyone with the diagnosis of possible problems.

 

[littlespark]

It looks likely the lid is touching the exposed copper on the black cable, but if the flex was deteriorated, then I’d expect some of the internal wiring to be not so good either.

It may not have worked for some time.

 

[telectrix]

as he says^^^. also those crimps look like they've been squashed with a hammer. there's bare copper exposed.get them redone with a decent crimping tool and make sure nothing can short out.

 

[Lucien Nunes]

when I plugged it into my outlet, which I later found out was a GFCI outlet, it caused the outlet to short.

Presumably you mean it caused the GFCI to trip? This could be due either to a short-circuit (e.g. where your hot or neutral wires are touching the grounded case of the motor) or a fault within the windings. With the power disconnected, use the 20MΩ range on the multimeter to measure between hot and ground, and neutral and ground. You are looking for a high reading. If it is low e.g. 0.01, click the range on the multimeter down to get the best reading you can as this can indicate what sort of problem exists.

As above the ring terminals are not properly attached - they need to be fitted using the correct tool with the insulation inside the plastic sleeve. But that in itself is not causing your GFCI trip unless the bare copper is touching the motor case.

 

[adamadamadam01]

Thank you all for the help! I will try these things and report back. Also, here is a picture of the original wiring, I matched up the new black and white wires to the same spots as they were in this original picture. Hopefully that's what I was supposed to do.

 

[adamadamadam01]

Edit: I was told by someone else that I might have the black and white cables in the opposite spots, and to use a multimeter to test this. However, I don't know what I need to do in order to determine if they are indeed in the correct spot

 

[Lucien Nunes]

The black hot wire should go to the switch. Swapping black and white would not trip the GFCI, it would still.work, only the motor would be live with tbe switch off.

Do the test I mentioned, from hot and neutral to the motor housing.

 

[adamadamadam01]

The black hot wire should go to the switch. Swapping black and white would not trip the GFCI, it would still.work, only the motor would be live with tbe switch off.

Do the test I mentioned, from hot and neutral to the motor housing.

Thank you. For the test, 2 quick questions. 1. Can I do it by putting the red wire metal lead from the multimeter on the prongs of the cord (1 at a time obviously and then then the black wire lead on the metal body)? Or do I put the red wire lead from the multimeter on the screw/nut where the wire is connected, or does it not make a difference which of the two I put the red lead on? 2. If I get a reading of OL while doing this would that be acceptable for what i'm looking for?

 

[Lucien Nunes]

No difference where you put the meter probe (prong or terminal screw) but make sure the switch is on. Yes you are looking for an OL indication on the highest resistance range if possible. This does not 100% guarantee that the windings are OK but it's a good start.