[diystephen]

A friend of mine recently bought a house (had a home inspector look at it) and I just got to see it for the very first time. It was built in '98 so I didn't anticipate the panel looking this bad...

 

[diystephen]

It's basically a mess of MWBC's with no breaker labeling or handle ties. Two MWBC's are wrapped with electrical tape, but the rest... Multiple MWBC's run through one conduit as seen below (there's actually five hote wires and three neutrals there). Two MWBC's and an additional circuit...

 

[diystephen]

I've already found one MWBC that isn't on opposing buses... I'm not sure what code cycle they were on back then. When did MWBC's start needing to be handle tied in code? In this case I will obviously help him upgrade to double pole breakers

 

[rjniles]

I wished my panel looked half that good. Minor issues, easily corrected.
Handle ties only became code in 2008.
Multiple circuits in a conduit is fine.

 

[diystephen]

I wished my panel looked half that good. Minor issues, easily corrected.
Handle ties only became code in 2008.
Multiple circuits in a conduit is fine.

Labeling the breakers and putting in the double pole breakers is straightforward, but it's a shame home inspectors are this bad nowadays. I thought 8 conductors in a conduit would need derating or pose a code problem. Is that not correct?

 

[rjniles]

Most HIs don't remove panel covers. Yes derating is required for more than 9 #10,12, or 14 conductors. Are there more than 9 in a conduit? Derating may be accounted for.

 

[diystephen]

Most HIs don't remove panel covers. Yes derating is required for more than 9 #10,12, or 14 conductors. Are there more than 9 in a conduit? Derating may be accounted for.

Only 8, but that's good to know. I thought it kicked in at less than that.

 

[rjniles]

It actually starts at more than 3, but does not get less than the normal capacity until you reach 9.

 

[joed]

Derating only counts current carrying conductors and MWBC only count as two not three.

 

[diystephen]

Thanks rjniles. I'm used to looking at panels from 30+ years ago, so the fact that MWBC's are such a huge part of a more recent panel was eye opening (although I can understand why it's done.) I also expected that the MWBC's would be labeled even if handle ties weren't required yet.

 

[Oso954]

Why do you expect a MWBC to labeled ?

There is an underlying assumption that people removing the dead front on a panel know what they are doing.

 

[diystephen]

Why do you expect a MWBC to labeled ?

There is an underlying assumption that people removing the dead front on a panel know what they are doing.

I guess for the same reason that code requires them to be handle tied now. When working on a MWBC circuit it would be important to kill both circuits when say removing the shared neutral on a receptacle.

In the case of this panel, I found an MWBC with two breakers on the same bus. It's possible that if they were labeled that may not have happened

 

[rjniles]

I guess for the same reason that code requires them to be handle tied now. When working on a MWBC circuit it would be important to kill both circuits when say removing the shared neutral on a receptacle.

If it is wired correctly there will not be a shared neutral on a receptacle. The neutral is pigtailed to the receptacle?

 

[diystephen]

If it is wired correctly there will not be a shared neutral on a receptacle. The neutral is pigtailed to the receptacle?

I actually meant to write circuit, but instead listed receptacle. You are correct though.

 

[Tom738]

I've already found one MWBC that isn't on opposing buses... I'm not sure what code cycle they were on back then. When did MWBC's start needing to be handle tied in code? In this case I will obviously help him upgrade to double pole breakers

By opposing buses, you mean a bus for each phase of the split-phase, and only one of the buses is feeding the MWBC? That should be changed immediately--it means the current on the neutral can be double what is permitted by code.

 

[diystephen]

By opposing buses, you mean a bus for each phase of the split-phase, and only one of the buses is feeding the MWBC? That should be changed immediately--it means the current on the neutral can be double what is permitted by code.

That's correct, and it was the first thing I addressed for him. There's a finished basement and circuits were obviously added for that after the home was built. I'm guessing during that process the two breakers of the MWBC were inadvertently placed on the same bus.

 

[diystephen]

I didn't have time to fully address the labeling of the MWBC's in this panel and I'm back at it tonight. I'm using a clamp ammeter to identify which of the 3 neutrals goes with the 5 hots that route through the top left conduit. I found that there are 3 different circuits using a single neutral. Here's a breakdown:

Below three share a single neutral of #14 wire
-,Gas furnace blower #14 (L1 of panel)
- Basement lighting and receptacles #14 (L1 of panel)
- Basement lighting and receptacles #14 (L2 of panel)

Last two circuits with individual neutrals
- kitchen island/outdoor outlet #12 wire
- hard wired smokes #14 wire

The question is the best way to remedy. I found where the furnace neutral pig tails into the basement lighting/receptacle circuits. I can remove furnace neutral at that point and run an individual neutral back to panel to put furnace on its own circuit (it is a long run back to the panel from that point however.) I can share a neutral with the smokes and turn that into a MWBC with furnace (that pig tail neutral connection Is slightly closer to furnace.) Last would be to create MWBC from the kitchen island/outdoor outlet to furnace, but that neutral pig tail branches off into a separate conduit from the furnace wiring, so that's really not an option.

Thoughts are welcome.

 

[joed]

I can remove furnace neutral at that point and run an individual neutral back to panel to put furnace on its own circuit (it is a long run back to the panel from that point however.)

I think this is your best option.