15 Amp Breaker Install

I am putting in a 15 amp breaker tomorrow for the electrical side of my RV water heater (120V, 12 amp load). The picture attached is the the RV panel; the main panel is outside the RV. The hot-neutral-ground line from the water heater is capped in the box, ready to hook up. I did extensive wiring on this place two years ago: refreshing my memory today.

Should I just put a single 15 amp breaker in the box or should I put in a dual as the rest of the breakers? I remember something about pairing breakers, even though the second breaker will not be used. Thanks!

 

Put in a regular breaker. If the water heater is 240V, use a 2-pole breaker.

 

Do you have one or two full-size breaker spaces left? Does your water heater need a 120V or a 240V circuit? Is that a 120/240V single-phase panel?

 

I think that's an 8 circuit 120/240v single phase panel used in a motorhome.

The water heater has a 1400w element and is a 120v 12a device.

There is a 2 pole main and 4 tandem breakers which leaves two full spaces open.
I believe the 2P50 is the main breaker.

 

I would install a tandem breaker (two singles side by side) as you have for the remaining circuits, leaving one half open for future expansion if you want. Not sure if that answered your question or not.

 

A tandem breaker and leaving one side unwired was what I was thinking about: I will install today. I want to place an extra outlet in the bathroom ahead and the empty side will set this up.

Two spaces are left open, but the cover seems to have only one knockout left and a depression for the last breaker position.

Yes, the water heater is a Suburban SW10PE - gas side is currently out and i wanted to get the 120 V electrical going. This is a RV and the electric element is 1400 watts at 12 amps. I will find out now why the water heater electrical line was disconnected at the box: I think it was to wire in a new appliance, but will find out. Thanks for the help!

 

A 15A circuit, as you suggested in your title, is sufficient for your 1400W water heater. The receptacle in the bathroom, OTOH, needs to be not only GFCI protected but supplied with 12AWG wiring on a 20A circuit.

I would suggest either a pair of half-size 20A breakers, if the wire for the water heater is 12AWG, or one 20A and one 15A, like you have next to the main breaker, if the existing wire is 14AWG.

 

The yellow jacketed line coming in is 12/2 WG NMB 600V which will connect to the 15amp breaker for the water heater. That's clear that a 20amp breaker is needed for a GFCI bathroom outlet and a similar 12/2 line in with ground.

It sounds like this 12/2 WG line may require a 20 amp breaker. Can 12/2 WG be used with a 15 amp breaker?

The cover says these are Square D Type QO breakers.

Thanks!

 

Yes.

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Suburban, manufacturer of the water heater, OKed a 20 amp fuse (12amp draw for the electric side), so it looks like a 15 (recommended) or 20 amp breaker (OKed) will work with the 12/2 WG NM-B 600V line, depending what is available out here - small town. I will try to find a 15amp (for water heater) and 20amp (for future GFCI) tandem breaker if available. Thanks for the help!

 

Will two single breakers work in the dual slot? Local hardware only has single pole breakers.

 

Do you have a Lowes store nearby? If not, you can order from Lowes online and have the tandem breaker in a few days.

Shop Square D QO 20-Amp Tandem Circuit Breaker at Lowes.com

 

Menard's has the 15 & 20 amp version. Others may too.

If not, two half-height breakers should work fine, so long as they're made to fit in that panel.

 

I am not aware of half height Square D breakers. GE and Crouse-Hinds had half height breakers, but neither would fit a QO panel.

 

Confirming breaker at hardware store, I called Square D (Schneider), and they said a single pole 15 would work with the RV QO Electric box model. The single 15 amp breaker is the full width of a tandem pole breaker, and the only breaker style available up here. I wanted to see if the electric side of the water heater would work, before spending a bunch of money - Albuquerque and Lowes are 60 miles away.

The line wired and volt metered well but the electric wire heater outside on/off switch melted. It did heat the water for awhile, but I had to switch the button on and off to get it to work. I had previously sprayed the switch with electric contact cleaner last week as the switch sounded rough - too much high plains weather. Now its inoperable and fused together. As this electric system is only a cheap switch, a light weight thermostat and high limit switch and a 14 dollar electric coil, it should not be too hard to troubleshoot. The water heater is ten years old. Thanks! Will update final outcome and may be going to Lowes after all.