Wiring for my new DC.

John Pollman

Member
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1,332
Location
Rochester Hills, MI
Hi folks,
I recently purchased the Harbor Freight 2hp 5 micron DC unit. It works OK, but I've had trouble getting it to start up at times. I'm pretty sure that it's because I only have 15A outlets in the basement at this time. I think I'm going to have to change that. But for now, I'm going to put in a dedicated 20A circuit just for the DC. Most of the time it will be on my table saw. So I think I'm going to install the outlet over near the TS so I can plug the DC directly into the outlet. But there will be times that I want to use the DC in other locations. I was planning on just putting one outlet on the circuit, but that limits where I can use the DC. Like I said, most of the time it will be in one place over by my TS.

I thought about picking up a short 25' heavy duty 12 ga. extension cord for times that I might want to move the unit. Then I wondered if it would be worth getting (or maybe making) a short 25' 10 ga. cord. The circuit would be 12 gauge so does it make any sense, or would there be any benefit to using a heavier gauge extension cord? I guess I could just install maybe another outlet or two in the circuit, thus avoiding the need for an extension cord at all. I'd really prefer to eliminate any extension cords if possible. Even when I plug this beast 2hp motor into the 15A circuit, it struggles to start, and sometimes won't.

I think I've got some electrical upgrades to make in the shop SOON. :)
 
There are some charts out there to show the max amperage's for distances of the various wire gauges. I'll see if I can locate one, but at the lengths you're talking about, 12 gauge would be fine. I'm not sure I've been running mine off of a 20 amp circuit. It's one of the older plugs in the shop and not sure of the wire/breaker size, most the older breakers were 15 amp. I know the cord is only a 14 gauge cord. Will have to re-evaluate mine when I get home, but it's been running fine on it.
 
Ahhh, I just discovered a problem...

I have three outlets that are mounted on the posts running down the center of the basement. One duplex outlet on each of the poles. I'd like to have two outlets at each of those locations. I traced the wire in that circuit and those three outlets are the only things on that circuit. It's all #14 wire, but the breaker controlling that circuit is 20A! Someone dropped the ball there and I never noticed it. I'm headed to the BORG in a little bit. I've got a coil of #12 wire already, but I'm going to pick up some new outlets and two gang boxes and rewire the entire circuit. I think I'll even get a new 20A breaker.

I just looked at the label on the DC and it says the motor is 120V/60hz./14A. It's a 20A breaker but the wiring is only #14. I'm gonna put in a whole new 20A circuit for those shop plugs and try the DC on that circuit. If it works fine, I'll just put in the dedicated 20A for the DC and be done with it. A #10 extension cord wouldn't hurt anything, it would just be less voltage drop.
 
Looks like we were all typing at the same time. ;)

Last time I had the problem, the unit was plugged into the outlet closest to the panel. It's only about 7' tops. Maybe 15' of wire from the breaker to the outlet. I just talked to my dad and he said that it sounds like maybe the start capacitor has a problem. Well since I want my power outlets in the shop upgraded anyway, I'm going to start there. Once I have a good quality 20A circuit installed, I'll try it out. If it doesn't start up correctly, there's a problem with the unit and I'll take it back to HF and have them replace it. I only bought it about 3-4 weeks ago.

Thanks for the input guys!
 
A (true) 2hp motor is stretching the capabilities of a 120V~ circuit on startup.

Since you're already rewiring a circuit, consider running a new, dedicated 20 amp 220/240V~ circuit, and rewiring your DC for 220/240. It'll draw less current (per leg) and probably start much easier.
 
I thought about that Jim.
A lot of bigger motors I've seen are capable of being rewired to run on 220. I can't find a label of any kind on this DC motor. I'll have to look in the manual. If it's possible to run on 220, I'll definitely do it.

I just got back from the BORG with the stuff to rewire the existing circuit. We'll see if that helps. I'll report shortly, it shouldn't take me too long to redo this circuit.
 
A (true) 2hp motor is stretching the capabilities of a 120V~ circuit on startup.

Since you're already rewiring a circuit, consider running a new, dedicated 20 amp 220/240V~ circuit, and rewiring your DC for 220/240. It'll draw less current (per leg) and probably start much easier.

The HF DC is 120v only.
 
...I recently purchased the Harbor Freight 2hp 5 micron DC unit...

Don't know if you're planning to do so already, but I highly recommend replacing the 5 micron bags with a pleated cartridge filter from Wynn Environmental. Not only will it improve the performance of the DC, it will do a much better job of catching the finer (<5 micron) and more dangerous dust particles. I've got the paper 0.5 micron model, but any of them would be a vast improvement over the cloth bags HF provides.

...I just talked to my dad and he said that it sounds like maybe the start capacitor has a problem...

I suspect he might be right. I ran my HF DC on a 15 amp circuit before I upgraded my shop circuits, and didn't run into any startup problems. That said, I think you're taking the right approach by upgrading your circuits as a first step in tracking down the problem. :thumb:
 
I thought about that Jim.
A lot of bigger motors I've seen are capable of being rewired to run on 220. I can't find a label of any kind on this DC motor. I'll have to look in the manual. If it's possible to run on 220, I'll definitely do it...

Take the cover off the box where the wiring goes inside the motor. Often, there's a wiring diagram for 120/240 on the underside of that cover. Many (most?) motors can be wired for either voltage just by switching a few wires in the junction box.
 
Take the cover off the box where the wiring goes inside the motor. Often, there's a wiring diagram for 120/240 on the underside of that cover. Many (most?) motors can be wired for either voltage just by switching a few wires in the junction box.

Not with the HF DC. It's strictly 120v only. Or at least mine is...I looked into it when I was converting my other big tools to 240v after the shop upgrade.
 
Well it looks like I got a bad one.
I finished upgrading the one circuit with the shop plugs on it top 20A. All new wiring, boxes, and 20A rated outlets. Finished up and flipped the breaker and everything worked fine. I plugged the DC into one of the outlets and hit the switch. It hummed for about 2-3 seconds and popped the breaker! It's going back. I bought it on March 22 so it's one month to the day. I called and they only had one left in stock so he said that he'd put my name on it and I could come exchange it any time. I'm loading it into the trailer now and might take it back tonight. But may wait until morning. I'll decide shortly. :)
 
Well it looks like I got a bad one.
I finished upgrading the one circuit with the shop plugs on it top 20A. All new wiring, boxes, and 20A rated outlets. Finished up and flipped the breaker and everything worked fine. I plugged the DC into one of the outlets and hit the switch. It hummed for about 2-3 seconds and popped the breaker! It's going back. I bought it on March 22 so it's one month to the day. I called and they only had one left in stock so he said that he'd put my name on it and I could come exchange it any time. I'm loading it into the trailer now and might take it back tonight. But may wait until morning. I'll decide shortly. :)

On the plus side, now you know you have good wiring in your shop. :thumb:
 
Yep! :)

I was pretty concerned when I traced back that #14 circuit to a 20A breaker!
But that problem is solved. Now I've got three two-gang boxes with 20A outlets wired with #12 wire. I just got back from exchanging the DC for a new one. While at HF, I picked up a 25' #10 extension cord. It was only $10 more than the #12. The larger wire will allow for a little less voltage drop.

Now I get to spend tomorrow morning assembling the new DC. Good thing I know how to now, because the assembly instructions that come with them are USELESS!!! Very vague and the diagrams are lousy. Also, the hardware they ship with the thing for assembly works, but it doesn't match what the instructions call for! :bang:
 
Well I went and exchanged it last night, but I didn't get around to assembling it until this morning. I finished assembly, checked things over, then plugged it in. Hit the switch and CLICK, there goes the breaker! :huh:

Well I think that I may not have reset the breaker after installing the new wiring and outlets. I hooked up the new breaker and clicked it into place and just flipped it on. I tested each outlet with a drill motor and things were fine. But this was the first big load put on the circuit. It definitely tripped and I started to get concerned. I flipped the breaker to the off position and then back on again and gave it another try. This time the DC fired right up. I let it run for about 30 seconds and shut it down. I did this several times and it seems to be fine. But I had another job to do today so I shut the lights off and headed off to work. I haven't done anything with it since. We'll see what happens next time I go down there and fire it up.
 
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