About two years ago, a landlord came on here and said "I want to get my 2 tenants to split the cost of running the dryer. I want to tap the red wire from tenant 1's panel, and the black wire from tenant 2's panel, so it rolls half on each electric bill. Make sense?" Of course, we had to take our shoes off to count the number of ways that violates the Electrical Code.
When the 200A breaker is on, we think the left side is supplying power to the right side via a 220V circuit for the hot water heater that's back feeding the right side.
Look at the red wire, lower left
All the circuits which are attached look to be in reasonable order, except that one. It goes onto half a 30A 2-pole breaker, and there's no partner black wire.
Now if you follow it to where it exits the box, it kinda disappears in the lower left corner. There is a same-size black wire which exits the picture out through where the panel cover is supposed to be, off to parts unknown. I assume that is the red's partner in the cable? And somewhere back there a white wire goes up and hits the neutral bar.
I suspect that this (presumably) 10/3 cable goes to a utility room, where it may have powered a water heater dedicated to this unit, until the landlord got the bright idea and decided to have one commons water heater.
However, I could be wrong for 2 reasons, and this may instead be happening with the 30A MP-T breaker above it, or the 50A breaker above that. I think that because first the breaker is off, and second parallax may be confusing me, but it looks like the red wire is attached to the right side bus not the left.
The dead giveaway would be if you switched the breaker off and the spook voltage went away.
Why does the water heater backfeed? Don't all electrical appliances work like diodes and block current flowing backwards through them? No, they're not, not at all. A water heater simply has a heating element of about 10 ohms in line with a thermostat, so when the thermostat is on, it's similar to a wire of long length.
This panel is the poster child for NEC 110.12
Aka "Neat and workmanlike". Which makes this kind of slop not a surprise, and casts shade on all the electrical work done in the building. First, don't misinterpret 110.12 as a call to runt back excess cable length; you actually want enough length for hots and neutral to reach any breaker in the panel. The problems are elsewhere:
- Alien breakers. This is a Murray/Siemens panel, and that Square D breaker definitely doesn't belong and will not clamp the power bus correctly, causing arcing and damage. I would also look carefully at the black breakers near that double-stuff breaker.
- "Enough length to reach any breaker in the panel" is correct! But that yellow cable is taking it a bit too far and should be shortened somewhat. Other than that, it's perfectly OK for the cable to remain in sheath for a distance inside the panel; all the better to letter it with a Sharpie saying what it is.
- The way the neural wires have floppy-dopped out of the bottom of the panel, makes me think this panel spends a lot of time with its cover off. The cover should be reinstalled when the servicer walks away from it (2 corner screws loosely set is fine; but you must stop curious fingers!) I've probably taken my panel covers off hundreds of times.
- The abandoned cables entering the top should have their conductors grouped by cable, lightly twisted together so they can be identified as related, tucked away from the panel, and their bare copper ends capped or taped off. The grounds don't need to be disconnected.
- All hot wires from the same cable must land on the same breaker, unless you know for sure the usage is correct (e.g. a MWBC with half held in reserve,
- Cables coming in through bare knockouts with no strain relief or cable clamps. They make donut adapters to reduce that huge opening to one that matches a cable clamp for whatever cable is coming in that hole.
- The loose Romex below the panel has no physical protection and needs that.
- +1 for workmanship separating neutrals and grounds. The wire-nut splices are fine.
Other than that, it's a perfectly fine panel if properly fit.
Can't work on a rental unit yourself
All work on any rental unit must be done by a licensed electrician, to assure quality work and no slumlord shortcutting (and this panel looks like it's full of that). Second, any work requires landlord permission. The only way you get away with self-repair in a rental unit is if you a) own it, b) are genuinely living there (meet the criteria for an owner-move-in eviction), and c) the type of unit is typically owner-occupied, i.e. a 2-unit duplex or 3-unit flat, but not a 12-unit apartment building.