My Jet Table Saw can run either on 120v or 240v. It is currently set up for 120volt. Is there an advantage to switching it from 120V to 240V?
Less amps means less voltage drop (voltage drop = current in circuit x resistance/foot in wire x length of wire). The motor will not receive the same voltage as the service transformer or house panel. It will receive voltage at the panel minus the voltage drop in the wire. Obviously the lower the voltage at the motor, the more current the motor needs to make the same power, which in turn raises the voltage drop.Less Amps? Easier for the motor to get the power it needs?
First, I need to disclose that I am not an electrician or inspector. But in research I was doing for my basement shop, it seems that the NEC only requires GFCI protection for 120 volt branch circuits. There's an authoritative site for NEC geeks -- mikeholt.com -- that provides good discussion of electrical codes without you going directly to the NEC.Mike,
I recently got a dedicated 240V circuit installed in my garage shop with the help of my neighbor. I didn't think about it until reading this thread, but we did not put in a GFCI breaker our outlet on the 240V circuit like we did on the 120V circuits that we also added. Am I understanding you correctly that even though it is in a garage that I don't need it to be GFCI protected because it is a 240V circuit?
Thanks for the info Mike, I have reached the point in my shop construction where I am installing receptacles. I put a GFCI in the box for the door opener and wired the drop cord coming from the ceiling to my center machines downstream from the GFCI I am thinking ANY protection I can give the opener electronics would be a help. I hope the plug in light exemption remains I am installing 7 eight foot flourescents all on plugs for possible future changes. I think that GFCI protection up at the ceiling is kind of overkill and I could do without the added cost of 4 more GFCIs. The lights will be wired in four banks.First, I need to disclose that I am not an electrician or inspector. But in research I was doing for my basement shop, it seems that the NEC only requires GFCI protection for 120 volt branch circuits. There's an authoritative site for NEC geeks -- mikeholt.com -- that provides good discussion of electrical codes without you going directly to the NEC.
A little off topic, but related: it's interesting that there is a new NEC code for 2008 that will change the rules somewhat for 120V circuits. Previously there was a GFCI requirement exemption for single outlet appliances (washing machine, sump pump, freezer, where the common usage was to snip the inside connectors on a duplex receptacle making a single outlet). These devices now require GFCI protection. I say interesting because there will be a whole lot of houses sold that will require retrofit if the inspector finds they don't meet code.
The other exemption was for receptacles out of reach (a garage door opener or plug-in lighting). I haven't read anything about whether the 2008 code rules changed for those, or for 240V ciruits.