15AMP vs 20AMP circuit for reloading room?

[Jbar52]

Good info here just finished
A project with a buddy like this

 

[jpndave]

Run a 14/3 wire (you have to pull a wire anyway). Come into a 2 gang switch so if you don't need all the lights don't turn them on. Use the red wire for lights and the black wire for the outlets and the common neutral. Install a 2 pole 15 amp breaker in the panel. 2 circuits and you are working with your lighter wire. Come out of the 2 gang switch with 14/2.

The problem is this post. We're talking about two 15A circuits off a double breaker on the same pole. Two 15A breakers supplying power to two 14 gauge supply wires (one black one red in the 14-3). You are then expecting a single 14 gauge (white wire in the 14-3) to return a potential of 30A from the two breakers ON THE SAME POLE so double the 110V NOT two opposing sin wave 110V opposite circuits yielding 220V and no return on neutral.

 

[jpndave]

It's 220/240v if the hot legs are coming off opposite bus bars in the panel. Otherwise they are just two legs of 110/120v operating in parallel. It would be absolutely no different that connecting 2 wires to a single pole 110/120v wire; they are both supplied by the same line in parallel. Electrical currents work in sine waves. 220v on opposite busses are opposite sine waves. The amperage through the lines is determined by the breaker, not by the amount of wiring.

Correct but look at my post just previously. It was advised to supply those two 14ga wires with two breakers to double the allowed amperage. This is absolutely correct that the breaker determines the amount of amperage allowed to pass. That's exactly the problem we are allowing double the amount that neutral should be protected for.

 

[Bill Nieters]

The problem is this post. We're talking about two 15A circuits off a double breaker on the same pole. Two 15A breakers supplying power to two 14 gauge supply wires (one black one red in the 14-3). You are then expecting a single 14 gauge (white wire in the 14-3) to return a potential of 30A from the two breakers ON THE SAME POLE so double the 110V NOT two opposing sin wave 110V opposite circuits yielding 220V and no return on neutral.

Wiring a split wire circuit such as you're talking about is completely illegal. The red and the black must be hooked to opposite phases in the panel

 

[jpndave]

Wiring a split wire circuit such as you're talking about is completely illegal. The red and the black must be hooked to opposite phases in the panel

Exactly!

We're not talking about 220v, he is doing 110v and using the 14-3 in that application is not safe.

OP, please run a single 12-2 connected to a single 20A breaker and be safe.

 

[jpndave]

The -3 wire (14-3, 12-3, 10-3, etc) is used for 220v (two opposing legs in a single phase application) as Bill keeps bringing up or as travelers for a 3 way (or 4 way, etc) switch circuit. NOT to cheat physics and breakers to save on wire.

 

[mwkelso]

Correct but look at my post just previously. It was advised to supply those two 14ga wires with two breakers to double the allowed amperage. This is absolutely correct that the breaker determines the amount of amperage allowed to pass. That's exactly the problem we are allowing double the amount that neutral should be protected for.

I see now, sorry I missed that part.
Running unbalanced is a definite no. That's asking for trouble.
Thanks for clarifying that.

 

[Troutslayer2]

Ok you talked me into running 12-2. My lights are on their own dedicated circuit. I intend to install all of the boxes, run all of the wires but bring in a pro to make the connections and install the breaker. Not because I don't think I can do it but it's just not that much expense to be sure it is done right. I'm not an electrician. 20AMP it is, it will be a little bit overkill but who knows what I might end up plugging in in the distant future.

 

[jpndave]

I see now, sorry I missed that part.
Running unbalanced is a definite no. That's asking for trouble.
Thanks for clarifying that.

All good! Normally I would just walk away when things start getting thrown around but this one could end up in a fire or someone dead. I "think" I understand where Bill is coming from on this. The -3 wire simply shouldn't be used as it is being proposed. A contractor wouldn't (or at least shouldn't) even think to do that. He just assumed 220V because that or the switch circuit is the only place an electrician would use that wire.

Your wording "unbalanced" is great, I should have thought to write that, thanks for the clarification.

 

[mwkelso]

The -3 wire (14-3, 12-3, 10-3, etc) is used for 220v (two opposing legs in a single phase application) as Bill keeps bringing up or as travelers for a 3 way (or 4 way, etc) switch circuit. NOT to cheat physics and breakers to save on wire.

Could the OP go from panel to outlet branch, then at the end of the line of outlets supply the switch box for either a 2-way or 3-way light circuit? That way he would not need separate circuits for lights and outlets and could save the money from setting another home-run. All presuming that the design is calculated for load correctly, per code in his area.

 

[Barrelnut]

I was kinda looking at it this way

OP has 9 Led cans and possibly a couple electrical scales and who knows maybe a powdered brass prep station.
.
9 x 15 watt Led cans = 135 watts
135 watts on a 110 volt circuit draws = only 1.2 amps
Say you want a max of 80% load on a 15 amp circuit. that = total 12 amps
12 amps - 1.2 amps = 10.8 amps
That leaves the op 10.8 amps to run all kinds of stuff.

A 2 HP 5 gallon shop vac draws about 7.5 amps
A Steel pin case tumbler draws about 1/2 amp
A RCBS Chargemaster draws about .04 amps

So, you could run all kinds of stuff AT THE SAME TIME and not use 80% of the 15 amp circuit.

Now if you plan on running a 1500 Watt space heater on the same circuit, that could be a problem.

 

[jpndave]

Could the OP go from panel to outlet branch, then at the end of the line of outlets supply the switch box for either a 2-way or 3-way light circuit? That way he would not need separate circuits for lights and outlets and could save the money from setting another home-run. All presuming that the design is calculated for load correctly, per code in his area.

Yes as long as all the wire is 12ga. You can not step down to 14ga on the 20A breaker even though the lights only use 1.2A and there is no way to plug in anything else, the wire would not be protected.

 

[flylo]

Hope he does't add a coffee maker or any kind of dryer. Things change so what's it going to cost to do it right? Have a fire caused by your reloading ammo room & what's your insurance going to say. Do it right + a little more.

 

[mwkelso]

Yes as long as all the wire is 12ga. You can not step down to 14ga on the 20A breaker even though the lights only use 1.2A and there is no way to plug in anything else, the wire would not be protected.

That's what I thought. Thanks