Electrical question on circuit breaker

[Jeff Monson]

I have 2 110 volt 15 amp circuits run to my garage, my dust collector is on one of them and it is in the non heated portion of my garage. Now that it is winter when I fire up the DC it pops the breaker now and then. Its about 30 degrees in the garage and I keep my workshop at around 60 when I'm working.

Can I put in a 20 amp breaker? Is it possible the DC draws more amps on cold startup?

[Rod Sheridan]

Hi Jeff, yes it is possible that the dust collector bearings are a little stiffer in the cold.

No, you probably cannot change the breaker to a 20 ampere type. Generally the wiring and devices are not rated for a larger breaker, however you could investigate this.

Regards, Rod.

[Michael Wetzel]

You need to check the size of the wire on that circuit. If it is *ALL* #12 you can move to a 20A breaker. If if any part if #14 I would stay with the 15A.

[glenn bradley]

I'm no electrician but I have learned that the breaker protects your wiring, not your tool. As stated, if the whole circuit; breaker, wire and outlet are rated for 20a you're good. Any weak link in the chain is the lowest common denominator.

[Tony Dietz]

The only possible solutions are

1.to run a new line with a 20a breaker
2. run a new 220v line and convert the Dust collector to 220 (it will draw less amps)

3. Check and clean the dust collector motor to make sure it's not loading up.

4. Turn power off to your house (main breaker) then tighten the wires inside the breaker box (for that line) as a loose connection can impead current. You might want to also check the connections on the outlet that the dust collector is plugged into.

[Jeff Monson]

Thanks for the quick replies, this house is new to me, (built in 1998) and I'm assuming all the wiring is #14's but I will check. I did run a 220 circuit for my tablesaw and combo planer/jointer but dont think it would support a DC running at the same time. The DC is a powermatic 1.75 hp and only about a year old, I know it can be switched to 220.

I'm just looking for my easiest option at this point.

Is it possible a new 15 amp breaker will help? (just wondering if they get weak after tripping a few times)

[Andrew Thuswaldner]

I agree that trying a new 15A breaker is a good idea. Sometimes they nuisance trip and as Rod has suggested the DC may be drawing a bit more current on a cold start-up. A very simple test would be to bring the DC into the warm part of the garage, wait an hour until it has had a chance to warm up and then try starting it up. If the breaker does not trip that suggests the problem is the temperature. You also might want to check the ratings on the dust collector to see if they recommend operation at such a low temperature.
Andrew

[Tom Veatch]

...Can I put in a 20 amp breaker? ...

If, and only if, the wiring is at least 12ga. The 15amp receptacles, as long as there is more than one outlet, are allowed by code on 20 amp circuits. A single, everyday, run-of-the-mill, 15 amp duplex receptacle qualifies as two outlets.

[Wes Billups]

I haven't seen anyone mention this. If the DC outlet is the only one fed by that circuit, you could install a 15 amp 220-V breaker and rewire the DC to use 220-V. This would cut your amp draw in half and you should easily be able to handle the load your DC is drawing with 14 awg wire.

Wes

[David Epperson]

All good points. A couple of other factors - since this system seems to be one the edge of the power capacity, at least during start up.
Cold air is more dense than warmer air and will take more power to move it, particularly at initial start up. You might try choking the system off, with a gate very close to the DC. Spinning up the impeller in a partial vacuum will take a lot less hp. Larger air compressors often do this to lower the initial indush of current on start up.
Also the idea of tightening up all the connections has merit, since copper shrinks due to cold temps and some oxidation in the connections wouldn't help either.
The plan to convert to 220 is probably best for a long term fix.

[Ken Gardiner]

One and 3/4 HP is 740 Watts X 1.75 or 1295 watts total. Assuming 110 VAC service as worst case, you would be drawing a running current of about 12 amps. However, start-up current could be much higher for a very short time and if high enough would trip the 15 amp breaker. I would substitute a 20 amp breaker to help give the extra margin of start-up service needed. Just keep the circuit in use for only the one machine and you should have no problems. I would not recommend adding more load to make use of the new found capacity, and would disable (tape over perhaps) other outlets on the circuit and/or apply caution labels. Also, you could have and insurance issue in the event of a fire, but that is a risk that might be acceptable to you since you will still have only a 12 amp running draw on the 14 gauge wires.

[Erik Christensen]

If you put a 20 amp circuit breaker on 14 gauge wire you have violated code. You get unlucky & have a fire - you have given your insurance company a bullet proof excuse to deny coverage - IMO not worth it.

try a new breaker
leave all vents closed - the more air flow the bigger the load - don't open till impeller up to speed
you could convert to 220v if nothing else is on the circuit - don't try taping over outlets as sure as heck someone will plug a 110v appliance into it with disastrous results

[Roger Frazee]

Wes gets the cigar.... Take a bow you nailed it. And your suggestion will likely take away any voltage drop issues.

I would be very surprised if a 15 amp branch circuit would support this dust collector over the long term without problems cold outside or not.

It is always best to understand the requirements of the equipment before shooting from the hip as to what you may be able to do with the branch circuit electrically.

You said this is a powermatic DC with 1 3/4 hp motor. A 1 3/4 hp motor is going to tax or exceed a 115 volt 15 amp branch circuit.


Powermatic at present only makes one model that is 1 3/4 hp either bag or cannister.

For motors 14 awg romex is allowed to carry 20 amps in the 60C column of table 310.16 NEC. And you can put a larger breaker like a 20 amp on that 14 awg to start your motor so long as the wire is big enough to handle the load.

Unfortunately 1 3/4 hp is a motor requiring 10 awg copper wired 115 volts if calculating from art. 430 of the NEC and using the FLC of table 430.248 x 1.25.

Powermatic recommends a 30 amp branch circuit for the PM1300 wired at 115 volts and a 20 amp branch circuit wired at 230 volts.

If you convert the wiring of the motor to 230 volts (easily done) and the branch circuit to 230 volts (need to know how to do this) you can keep the 14 awg and install a 20 amp double pole breaker but it will likely be fine with a 15 amp double pole breaker if wired 230 volts.

Here is the link to the DC manual. The electrical requirements are on page 13 converting the motor to 230 volts is on page 20.

A 15 amp 115 volt branch circuit was way to borderline for continued reliablity of that dust collector IMO.


http://content.powermatic.com/manuals/1791077CK_man.pdf

[Jeff Monson]

These posts are some great information, thanks a million, there are other outlets on this circuit also so converting this branch to 220 wont work. I have ran this DC all summer long with no issues until the weather got cold. I will install a new 15 amp breaker and try choking the air flow on startup this weekend and post the results as its going to be cold out. If there is any chance of loosing any insurance coverage this IMO is not worth the risk to me.

[Roger Frazee]

These posts are some great information, thanks a million, there are other outlets on this circuit also so converting this branch to 220 wont work. I have ran this DC all summer long with no issues until the weather got cold. I will install a new 15 amp breaker and try choking the air flow on startup this weekend and post the results as its going to be cold out. If there is any chance of loosing any insurance coverage this IMO is not worth the risk to me.

Forget the insurance worry, I'm not sure why so many people think their insurance won't cover them if a DC branch circuit isn't installed correctly by the homeowner.

Jeff


If you could get me the fla amps off the motor nameplate that would go a long ways towards determining whether you can continue to expect the 14 awg to support this DC.

Briefly explaining the breaker needs to hold the inrush current which can be as much as 6 times the running full load amps. After that the breaker is 15 amps so the load of the motor needs to stay at that or less during normal running conditions. 14 awg is rated 20 amps you are allowed for motors to increase the size of the breaker up to 250% to get the motor to start...unless the manufacturer states otherwise.

However it is not code compliant to operate the motor on a general purpose branch circuit with 14 awg and upsize the breaker. It would have to remain 15 amps. You must dedicate the branch circuit as a motor circuit in order to upsize the breaker.

Doing a little research I discovered the fla of the motor for the PM1300 is 15 amps. So your right at the limit of the breaker if the DC is operating at full load current.. If the branch circuit was dedicated to the DC I wouldn't lose any sleep upsizing the breaker to 20 amps on the 14 awg so long as your not too far away from the breaker box. But this is not the proper branch circuit for this motor. This is the "lets get resourceful branch circuit" ... and your motor is likely to suffer over the long term.

I don't know if you said or not but are you operating anything at the same time with the DC when you start it ? You have no room for additional loads.

How far is the DC from the circuit breaker panelboard?

Like it or not your present branch circuit is not recommended by powermatic for the DC when the motor is wired 115 volts. I do not think a 15 amp breaker will be reliable to hold the inrush current at start-up with this motor. It is also going to have excessive voltage drop at start up and will struggle to maintain proper amperage to the motor ...causing the life of the motor to shorten and the performance to begin to become noticeable. Once the motor is running the 14 awg and breaker will hold the running amperage but you really tax the motor at start up with this small wire.

This very well could be your issue and not the cold weather.