Amp Requirement Question

[Don Bullock]

Hopefully this is a simple question that one of our electruical experts can easily answer.

I'm thinking of buying a 110 volt jointer rated at 13 amps maximum load. Will it run on my 15 amp circuit?

Also see new question in post #5

[Randy Klein]

I'm going to guess that the startup amperage draw (usually more than the max load draw) will flip your breaker. Happened to me, so I upgraded to 20 Amp. Though I'm no expert.

[Jason Beam]

Run? Probably. Start? Maybe not. You're right in the range of "maybe" there. The rule of thumb is never to exceed 80% load. 80% of 15a is 12a, so i'd probably consider either upping the circuit or switching to 220 if possible.

Consider that you're really going to want a dust collector or vacuum on that jointer to pick up the chips, for sure. In the scenario you have, at the LEAST it'd have to be be on a different circuit.

[Geoff Grant]

Hi Don,

Well I'm not an electrical "expert" but I've done a bit of research for my own shop challenges. As long as the jointer is wired for 110/115/120 volts and not 220/230/240, you should be fine as long as you do not try to run anything else on that circuit concurrently (especially another high draw item like a vacuum, a dust collector or a ventilation fan). Also keep in mind that your 15 amp circuit may serve multiple outlets and lights - best to figure out which those are ahead of time. Electric Moters "pull" significantly higher amperage than the "running" max rating on "start-up" and therefore may trip the breaker on start-up if you have another load on the circuit. If you consider running new 110 circuits for the shop, I would use 12 gauge wire and a 20 amp breaker for maximum flexibility. If your circuit has a 15 amp breaker, it likely uses 14 gauge wiring. Do not "upgrade" it to a 20 amp breaker unless you are also upgrading the wiring to 12 gauge!

Hope this helps.

[Don Bullock]

That's what I thought. Why then doess grizzly recommend that their 1 hp 6" jointers be hooked up to a 15 amp circuit? It doesn't make sence. Thanks.

[Greg Funk]

Hopefully this is a simple question that one of our electruical experts can easily answer.

I'm thinking of buying a 110 volt jointer rated at 13 amps maximum load. Will it run on my 15 amp circuit?

Also see new question in post #5
It should run just fine. There are lots of 110V routers and saws that are rated at 15Amps and they don't have any problem so I can't understand why a 13Amp jointer would have any issues.

Greg

[Mike Henderson]

That's what I thought. Why then doess grizzly recommend that their 1 hp 6" jointers be hooked up to a 15 amp circuit? It doesn't make sense. Thanks.
One HP is about 750 Watts. Given that the motor is not 100% efficient, let's call it 1,000 Watts. On a 115 Volt circuit, that motor would draw about 8.7 amps, well below a 15 amp breaker.

I suspect the 13 amps specified is the starting current.

Mike

[Howard Acheson]

>> Will it run on my 15 amp circuit?

Is there anything else on the circuit? 15 amp circuits are generally restricted to lights and small appliances.

[Don Bullock]

I have other circuits in the shop (garage) only the jointer would be on even if I used a vaccuum for DC/all lights are on a different circuit.

Here is the response I got from Grizzly:

Thank you for your email dated July 25, 2007.

Thank you for contacting us with your questions. A 15 amp dedicated circuit is recommended for the G0604 Jointer. Also, a 15-amp dedicated circuit is recommended for the G0452 Jointer.

The 15-amp breaker in each circuit will provide the most protection for each machine. Each breaker should trip when the machine on its circuit is drawing approximately 15 amps for a period of time.

Since the motor on the G0604 should not pull more than 13 amps, a 15-amp dedicated breaker would provide adequate protection for this machine. Also, since the motor on the G0452 should not pull more than 14 amps, a 15-amp dedicated breaker would provide adequate protection for this machine. The proper 15-amp dedicated breakers would allow each machine to start and run properly.

[Randy Klein]

It should run just fine. There are lots of 110V routers and saws that are rated at 15Amps and they don't have any problem so I can't understand why a 13Amp jointer would have any issues.

Greg

I think universal motors rated at 15 amps draw less current at start up than an induction motor rated at 15 amps at start up. Since there is a necessary surge of energy needed to "fill" the inductors...

[Larry Fox]

The numbers they gave you are probably Full Load Amperage. If it is not a ton of trouble I would pull in a 20A just to give yourself some room.

I faced the same issue over the weekend where I was questioning it. Bit the bullet and pulled in a new circuit. Took about an hour including moving a workbench and patching to drywall.

[Rick Christopherson]

There is a lot of misleading information in this thread, but I won't go so far as to call it misinformation just yet (but close). You are permitted to use the full capacity of the circuit. As an end-user, you do not need to worry about loading the circuit to only 80%. That is something built in to the design of the circuit.

Your jointer will not likely draw full load amps very often, so even if the motor was rated at 13 amps, it will draw about 6 to 10 amps ranging from "Idle" to "normal" loading. By the time you get to the full load amperage of 13 amps, you will already be noticing the motor is significantly bogged down and nearing its stall-point.

Most circuit breakers are rated for the short-term start up current. Regardless whether the breaker is rated for this or not, you DO NOT take this into account when sizing a circuit. You take this into account when selecting the correct Style of breaker, not its size. If you have an old fuse panel, then you may run into more problems of tripping on start up unless you get a slow-blow fuse.

The bottom line is that if the tool was designed and certified to run at 120 volts, then 90% of the time, it was certified to operate on a 15 amp circuit.

More importantly, this is not something you need to worry about unless and until you experience frequent breaker tripping. If the breaker doesn't trip, then all is well. This is the reason why the NEC has specifications for creating a circuit, so you (as the end-user) don't have to worry about it, nor even understand it.

[Pete Bradley]

Why then doess grizzly recommend that their 1 hp 6" jointers be hooked up to a 15 amp circuit?

Because Grizzly likes to claim that a circuit breaker takes the place of the overload protection that should have come with the machine.

If they're recommending a 15A circuit and you have one with nothing heavy on it, it should run. You should still consider a mag starter with overload protection.

Pete

[Don Bullock]

Thanks to all for the replies. I hope this information will help some others as well.

I decided to go a different direction and just placed an order for the Grizzly G0490 8" Jointer that runs on 220. I'll use the same circuit that I run my SawStop on.:D

[Alan Tolchinsky]

Grizzly's reply makes no sense to me. They're implying the circuit breaker protects the machine. But it actually protects the wire in the circuit from overloading. Anybody understand the logic in their answer?

[Jim Becker]

Grizzly's reply makes no sense to me. They're implying the circuit breaker protects the machine. But it actually protects the wire in the circuit from overloading. Anybody understand the logic in their answer?

Alan, you are correct. The breaker protects the wire/circuit...in a sense FROM the machine!

[Roy Wall]

Thanks to all for the replies. I hope this information will help some others as well.

I decided to go a different direction and just placed an order for the Grizzly G0490 8" Jointer that runs on 220. I'll use the same circuit that I run my SawStop on.:D

Good move Don.......nice upgrade!

I do the same thing on my 220v circuit.....one machine at a time..:cool:

[Tom Veatch]

Grizzly's reply makes no sense to me. They're implying the circuit breaker protects the machine. But it actually protects the wire in the circuit from overloading. Anybody understand the logic in their answer?

There is no logic to their answer. The person who wrote that reply seems to be laboring under a popular misconception that the breaker somehow protects the load. As you stated, the purpose of the breaker is to prevent overloading the circuit wiring and any "protection" it might provide to the load it purely secondary.

I read the answer as meaning that a 15amp circuit was sufficient to start and run the machine.

[Don Bullock]

Good move Don.......nice upgrade!

I do the same thing on my 220v circuit.....one machine at a time..:cool:

Thanks Roy. I decided that at my age this would be my first and final jointer.;) :D