Any electricians in the house?

RainMotorsports

RainMotorsports

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So I am planning some rewiring on the second floor of my house. As far as that goes I have no real issues. My problem is how the secondary breakers are setup.

So upstairs we have 6x 20 amp breakers. The fucking stair light has its own 20 amp switch. I mean wtf. Putting that light on the circuit for the hallway + bathroom light.

So like a smart person I wanted to know the amperage on the mains. We have a 200 amp main, the Kitchen Breaker has a ganged pair of 25 amp breakers (3 outlets total) not including the dedicated 220/240's for the stove and dryer.

But the breaker for up stairs is a single 30 amp... what the fuck. Now honestly right now that isn't an issue. 2 lighting circuits 2 bedroom circuits dual outlets each and then the main bedroom has 4 outlets across 2 20 amp circuits. The bedroom is where 95% of the power usage is. 2 computers and an entertainment center. We probably dont reach 15 amps on a bad day. What my concern is once the bathroom gets remodeled I want an outlet in there. What happens when we are gaming full tilt and someone uses a hair dryer...
 
After a close inspection it appears the subpanel is wired 120v (as suspected via the single pole breaker) via 8 Gauge 2 conductor wire. In theory I could upgrade the breaker in the main panel to a 40 amp. The other option would be pulling $200 worth of 6/3 and wiring the sub panel for 220/240.
 
Number 8 wire is good for forty amps. In some cases up to 45 amp depending on the type of the wire ie thn thhn, thw etc etc. Is a ground wire run along with the 2 #8's ? As I remember they figure 1.5 amp per light and outlets any motor loads are figured differently . So lets say you had 4 lights and 4 outlets. 8x 1.5 amps = 12 amps for figuring out rough estimates in outlet and lighting loads. remember that when your figuring loads that the wire you run is figured out 80% of wire capacity. You never figure 100% of what the wire can carry. wire load example. that #8 wire they have already running up there you'd figure this way. #8 is rated for 40 amps. Since you only figure 80% of that 40 amp the total safe load on the wire is 32 amps. This is a safety built into the codes as not to ever run the wire to its max load capacity. All wiring should be done this waY. Check with local codes but I think I'm right on this. Ive'd been out of the field for a long time but thats the way I was taught to figure out layout of any circuits.
 
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@1968USMC Amps per light hahaha. The majority of lights in my house are 72 milliAmps a piece. I have 1 bulb that is maybe a hair over 1/10th of an amp. So a large room might use 1.5 Amps worth of lighting. I no longer care about lights being left on in the house. LED is a godsend.

Right now I am at 2 bulbs per room in half of the house and 1 in the smaller rooms. The kitchen is the only exception. Eventually I am thinking 4 8 watt bulbs in each room.

I have a killiwatt which helps per device or per powerstrip. For example I know my gaming computer pulls 375 watts from the plug even though Nvidia says the minimum power supply should be 550 watts we now know 450-475 might have worked. I have a 750 watt power supply whose efficiency curve happens be best right where my top end load is. A clamp might be nice for measuring entire circuits though.
 
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That 1.5 amp per outlet is a quick way to figure rough amps loads to figure wire sizes.
 
Amprobe is a great tool and I still have mine and use it when you need to know for sure whats going on. Guessing dont cut it in most all cases.
 
how many "amps" does that power supply pull? Dont forget printers, monitors, etc, etc.
 
1968USMC said:
how many "amps" does that power supply pull? Dont forget printers, monitors, etc, etc.
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Would depend on what the actual voltage is but 3 to 3.5 would be the assumption at the peak wattage.

Right now I actually have my PC plugged into the dedicated circuit for the window air conditioner. It is not even on the sub panel I am mentioning. But come summer time it will be. I always figure my desk at 1500 watts no matter whats on it. So thats an entire outlet, and most of the 2 outlet 10 amp branch. As it turns out 1500 watts is 80% of 1875. This was not on purpose lol
 
1500 watts at 110 volts would be just about 14 amps 12 /3 with ground 20 amp breaker for that circuit. Thats about max for that l,ine
 
When figuring wire sizes out always figure max loads as you know someone is always adding this and that to loads.
 
1968USMC said:
When figuring wire sizes out always figure max loads as you know someone is always adding this and that to loads.
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I actually can't get 12 gauge indoor wire at home depot. Found that kind of weird. Other than cost I have no objection to running 10 Gauge.
 
12/3 with ground if you want to carry 2 circuits along with ya instead of running two wires.
 
1968USMC said:
12/3 with ground if you want to carry 2 circuits along with ya instead of running two wires.
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Problem with that is you have to run a double pole breaker they cant be separate and they have to be on different legs of the sub panel which is impossible as this sub panel is wired for 120v, splitting the hot to both legs. Im not sure what revision of the NEC we are even on here. As of 2013 Baltimore uses NEC2011.
 
RainMotorsports said:
After a close inspection it appears the subpanel is wired 120v (as suspected via the single pole breaker) via 8 Gauge 2 conductor wire. In theory I could upgrade the breaker in the main panel to a 40 amp. The other option would be pulling $200 worth of 6/3 and wiring the sub panel for 220/240.
Click to expand...
Where is that 8ga wire coming from?
 
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