Shopsmith Forums

ugly_guitar_guy wrote:This is great, and a perfect example or what must be going on with the power in my garage. It's probably a 20A circuit then since I'm not tripping the breaker, but I'm just getting that huge voltage drop in the beginning. I'll just make sure to always start it slow. Thanks dusty!

The video depicts what I consider a normal voltage and current condition at startup but this does not mean that there is nothing to be concerned about in your apartment/garage situation.

My circuit is protected with a 15amp breaker and is being fed by a #10 home run that is about 65'-70' long. I routinely check the screws that secure the wires to the breakers in the breaker panel and the outlet box in the shop. I am operating in a moderate climate. Seldom is the temperature in my shop below 50°F. These factors can all contribute to different power performance characteristics.

Voltage problems are nothing to be scoffed off as normal if one does not have good technical reason to believe they are normal. Not knowing your technical background, I must say - be cautious NOT FOOLISH.

I found that wire size calculator interesting as well as some others linked to from there.

They seem to be consistent with each other. They all include a safety fudge factor which is reasonable.

Linking to the wire resistance calculator, and using #8 and 140' (70 out and 70 back) yields .084 ohms.

For 25A that gives a 2.1v drop(1.05v in each conductor.

The voltage drop calulator gave 2.4v drop.


Now some 'code' considerations regarding what ya did(and may do).

IIUC you initially had a 30A breaker in the main panel(which did not trip) and increased that to a 40A breaker. #8 ok for 40A feed, but length questionable. Like I said already #6 woulda been better(hindsight). After all 25A was what you used as input to that calculator, then changed the 'rules' by using 30,40 A breakers.

Also AIUI you have a 60A panel in the workshop. Does that panel have a 60A panel breaker on the incoming feed wires? It 'should be' the same size as the breaker 'feeding' it from the main panel.

At least that is what 'the code' said the last time I read it(been quite a while).

I would not be too concerned re the incoming breaker on the sub panel, but recognize it's application here is questionable. Since the status quo is unlikely to to push to the limit I think risk is acceptable(As long as that 40A breaker in the main panel does not grow)(again). Truth be known, that 30A breaker was prudent. It would let you know when the shop is getting too 'greedy'. Although that would not be very convenient nor safe if suddenly in the dark with machinery coasting down.

Now a 'gee it would be nice if correct' scenario.

Assuming the 30A and 40A breakers that fit the main panel also fit the sub panel(a big assumption, but if adding a panel myself, I would use a compatible sub panel box), leave the 40A in the main panel and install the 30A as in incoming feed to the sub panel. If the 30A will fit where an existing 60A breaker is, good. If not(or it doesn't have any) two of those 6 positions need to go to the incoming 30A breaker.

If your heart is set on 6 circuits, get 4 half size breakers for the lights and outlets. Those 'spare' 20A breakers can be future main panel breakers.

beeg wrote:I'd say it's a 15 amp circuit.

Ditto! If a 15A circuit, it is wired with #14 wire which has 50% more resistance(therefore 50% more voltage drop) than a #12 20A circuit which is limiting the current draw at the breaker. There is also the drop(??) from the main to the laundry room panel.

Easy enough to look at the breaker.

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judaspre1982 wrote:Come Spring I will make any changes necessary for safety sake.
I will do my homework in the mean time.

Thanks to all who responded to my posts.

Dave

40 40 is ok! #8 is the right size for 40A. 70' is marginal, but ok.

Codewise for typical lengths, 15/20/30/40A use 14/12/10/8AWG.

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Hi

I don't know if you have the same switch as the my Mk V but I had a problem with the switch and was able to take it apart (the front unclips from the body of the switch) clean up the terminals amd reassemble. The switch now works perfectly.

grahamqt wrote:Hi

I don't know if you have the same switch as the my Mk V but I had a problem with the switch and was able to take it apart (the front unclips from the body of the switch) clean up the terminals amd reassemble. The switch now works perfectly.

When you say "clean up the switch" does that mean dust it out or burnish the contacts?

I am not going to try with a new switch but I believe the switches from Shopsmith cannot be taken apart and reassembled.

While I was very quick to replace a switch on a customers item in the store (a liability thing) I have gotten hundreds of switches working on my own and family stuff over the years by usually spraying WD-40 in around the base of the switch toggle and flipping the switch quickly and repeatedly (item unplugged from the wall) or in some cases blowing into the switch with compressed air and flipping it.
Stuff never quits when you have a new switch handy or especially if you have a new switch handy and have the time to replace it both.
Sometimes that got things going to get me by on that job and I replaced it later but often the switch never failed again. Funny stuff happens...


.

I think that's the same switch I've used on mine & several others with no problems over time. Isn't the rating 10amp/220volt, 20amp/110volt? Aren't they inversely proportional?