Wiring bathroom to code

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Old 02-16-17, 04:15 AM
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Wiring bathroom to code

As part of my snowballing project of simply removing the carpeting in my bathroom, I noticed the following;

14-2 line from breaker box (15a) to 3-gang box.
Gang box to 1) center light, 2) center vent, 3) vanity light, 4) GFCI receptacle

Pretty sure this is not up to code if only because it's on a 15a breaker (and uses 14-2). Even if it were code, I'd like the receptacle on a different breaker since I have the room in the box.

May 1;
1) Keep 3-gang the way it is, and have a separate 20a to the receptacle?
2) Considering future upgrades; Run 20a to 3-gang, keep the 14-2 to the switches (and lights), run separate 20a to receptacle?
3) lazy approach, but I'd like to know; keep all bathroom wiring how it is, but use 12-2 and a 20a breaker to get to the 3-gang box?

While I'm asking questions; is there a mnemonic device to remember which is Line and which is Load?

Thanks
 
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Old 02-16-17, 05:02 AM
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Probably was up to code at one time,no real need to change it,however you could bring a 12/2 to the box and connect the GFCI receptacle to that if you like assuming the conductor fill in the box would be OK
Geo
 
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Old 02-16-17, 06:47 AM
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I certainly hope that it was code when installed.

My main concern is that this is a rental unit and the breaker box is in the sort of basement that my fiance would never enter. I wouldn't want the entire bathroom dark just because someone wanted to use a hairdryer. Since I'm already opening up walls, I'd like to allow for future install of a vent with heat.

To verify;
12/2 20a to the gang box with 14/2 for switches AND GFCI is fine?

If I wanted to;
12/2 20a to receptacle is fine
separate 12/2 to gang box with...
a) 14/2 to vanity lights
b) 14/3 to exhaust and light
d) ??/2 to the heater part of exhaust/light

OR, does the heater need its own run to the breaker box?

I don't really want to tear apart my ceiling, so I might not actually run a new line for a heater. But I'd like to know what is needed if I ever do.

Thank you
 
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Old 02-16-17, 08:12 AM
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14/2 to switches/light only if on 15a breaker. So new 12/2 on 20amp just to GFCI receptacle.

Combo fan/heater is fine on 15a circuit with 14/2 as long as there is no receptacle on same circuit. Technically not allowed to have vanity lights on same circuit if heater is over 50% of 15amp load.

Note some combo light/fan/heaters specify a 20 amp and/or dedicated circuit in their installation instructions. This supersedes code. And if 20amp you need 12/2, sometimes two 12/3s to feed unit from switch box to get light/fan/heater/nightlight. If over bathtub may need gfci depending on instructions. GFCI breaker or dead front.

Summary: 3 circuits recommended. 20a to GFCI receptacle, 15a for vanity lights, 15 or 20a for heater/fan
 

Last edited by Astuff; 02-16-17 at 08:59 AM.
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Old 02-16-17, 08:38 AM
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You could leave the lights on this circuit and add a 20 amp circuit with 12 ga wire/cable but you cannot use 14 ga wire on a 20 amp circuit so your plan will not work.
 
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Old 02-16-17, 08:39 AM
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14/2 to switches/light only if on 15a breaker. So new 12/2 on 20amp just to GFCI receptacle.
That contradicts my understanding of what I read on another forum. Please forgive my request for clarification;

If I were to run a single 12/2 20a to a gang box, all the wiring from the switches to the fixtures must also be 12/2? This seems a bit odd since most of the wiring in the fixtures themselves are 18 gauge or thinner.

Combo fan/heater is fine on 15a circuit with 14/2 as long as there is no receptacle on same circuit. Technically not allowed to have vanity lights on same circuit if heater is over 50% of 15amp load.
Does the heater fixture generally state amp draw?

Thanks
 
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Old 02-16-17, 08:55 AM
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If I were to run a single 12/2 20a to a gang box, all the wiring from the switches to the fixtures must also be 12/2?
Yes. A 20 amp circuit requires all wiring to be 12 ga. Don't start thinking about cords attached to or wires run within fixtures, this is just the wiring to the receptacles.
 
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Old 02-16-17, 08:59 AM
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If I were to run a single 12/2 20a to a gang box, all the wiring from the switches to the fixtures must also be 12/2?
That is correct.

Does the heater fixture generally state amp draw?
The heater may just state the wattage. To get the amps, divide the wattage by the voltage.
 
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Old 02-16-17, 09:56 AM
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A 20 amp circuit requires all wiring to be 12 ga.
Ok. Glad I checked on that.
 
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Old 02-16-17, 10:17 AM
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Combo fan/heater is fine on 15a circuit with 14/2 as long as there is no receptacle on same circuit. Technically not allowed to have vanity lights on same circuit if heater is over 50% of 15amp load.
The heater may just state the wattage. To get the amps, divide the wattage by the voltage.
So, if I wanted a heater on the 12amp circuit that includes vanity lights, the heater needs to be 825 watts or below? (825/110=7.5)? Otherwise, I need a dedicated line?
 
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Old 02-16-17, 10:52 AM
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900W or below. The nominal voltage is 120V.
 
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