Should I even care about this?

Status
Not open for further replies.

CFL

Member
I was on a job, not mine, and the guy had me wiring up some relays to control an appliance. I did as he asked, but the install just didn't seem right. I don't see anything dangerous, but do see code violations (I think). I just want to know if I'm the only one who cares about this kind of stuff. I always try to be code compliant if for no other reason than to pass inspection.

The circuit feeds a range. The two ungrounded conductors leave through the top of the panelboard, through a 3/4" conduit 3" long, and into a 12"x12" box. In that box they connect to the line side of a general purpose contactor. Then, off the load side, they exit through another 3/4" into the original panelboard and meet up with the neutral and they all leave together to the range receptacle. The 120v coil of the contactor is fed from a tap off of the line side of same contactor, and is controlled by a 24vDC ice cube relay in the same box. A 12awg grounded conductor is routed from the neutral bus in the panelboard, up to the box through one of the 3/4" conduits to power the 120v coil. I realize that this is going to work problem free, but is it wrong? Opinions?
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Electrically, the grounded conductor should be in the same nipple as the line-side of the contactor.

NEC-wise, the #12 wire isn't protected by the range breaker size (I'm guessing.)
 

yired29

Senior Member
Electrically, the grounded conductor should be in the same nipple as the line-side of the contactor.

NEC-wise, the #12 wire isn't protected by the range breaker size (I'm guessing.)
are you refering to 300.3 (B) Conductors of the Same Circuit. All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors and bonding conductors shall be contained within the same raceway, auxiliary gutter, cable tray, cablebus assembly, trench, cable, or cord, unless otherwise permitted in accordance with 300.3(B)(1) through (B)(4). Because thats what I was thinking
 

CFL

Member
Electrically, the grounded conductor should be in the same nipple as the line-side of the contactor.

NEC-wise, the #12 wire isn't protected by the range breaker size (I'm guessing.)

Yeah, that's along the lines I was thinking. Like I said, I know this will work but I don't want to give the inspector a reason to fail a job.
The breaker is 50amp and the conductors are #8's. The tap conductor is #12 as well as the grounded conductor to the coil. The #8 grounded conductor is not routed up to the relay box with the others. None of this is UL listed as an assembly (I know you're laughing). This is all easy to build, but it should be just as easy to build to code.
 

yired29

Senior Member
we stray from the rule of 300.3 (B) all the time with lighting switches hot in switch leg out but no neutral.
 

CFL

Member
we stray from the rule of 300.3 (B) all the time with lighting switches hot in switch leg out but no neutral.

That doesn't cause inductive heating. I don't know if what I am talking about would cause inductive heating either.
 

Power Tech

Senior Member
I was on a job, not mine, and the guy had me wiring up some relays to control an appliance. I did as he asked, but the install just didn't seem right. I don't see anything dangerous, but do see code violations (I think). I just want to know if I'm the only one who cares about this kind of stuff. I always try to be code compliant if for no other reason than to pass inspection.

The circuit feeds a range. The two ungrounded conductors leave through the top of the panelboard, through a 3/4" conduit 3" long, and into a 12"x12" box. In that box they connect to the line side of a general purpose contactor. Then, off the load side, they exit through another 3/4" into the original panelboard and meet up with the neutral and they all leave together to the range receptacle. The 120v coil of the contactor is fed from a tap off of the line side of same contactor, and is controlled by a 24vDC ice cube relay in the same box. A 12awg grounded conductor is routed from the neutral bus in the panelboard, up to the box through one of the 3/4" conduits to power the 120v coil. I realize that this is going to work problem free, but is it wrong? Opinions?

Why do you want to control a range?

Why don't you just feed the appliance and call it a day?

That's weird.
 

iMuse97

Senior Member
Location
Chicagoland
we stray from the rule of 300.3 (B) all the time with lighting switches hot in switch leg out but no neutral.

That's not a violation of 300.3(B) nor is it a problem for inductive heating, which is why it is not a violation.

300.3(B) just says that all conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors and bonding conductors shall be contained within the swame raceway, ....cable, cord, etc.

The reason is that the hot and switch leg cancel out any induction because the current is in opposite directions at any given moment on these two wires.
 

iMuse97

Senior Member
Location
Chicagoland
What if you want to make sure you didn't leave the oven on? You can turn it off from anywhere in the world.

Not bad! I've been told that soon enough we will be able to do this with all appliances, etc, in the smart home. You've just jumped the gun.
 

CFL

Member
Not bad! I've been told that soon enough we will be able to do this with all appliances, etc, in the smart home. You've just jumped the gun.

It's actually for a firehouse. When they get an alarm, the range turns off.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Like I said, I know this will work but I don't want to give the inspector a reason to fail a job.
The breaker is 50amp and the conductors are #8's. The tap conductor is #12 as well as the grounded conductor to the coil.
In that case, the #12 hot wire should be supplied by a 20a (or less) breaker, not a 50a.

The #8 grounded conductor is not routed up to the relay box with the others.
That is an issue because the four #8's aren't in a single nipple. Either they should be, or the #8 neutral should be routed through the box.

None of this is UL listed as an assembly (I know you're laughing).
I'm not laughing at all. I often do what you're describing when adding an appliance to be deenergized by an existing Ansul-type kitchen system.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
we stray from the rule of 300.3 (B) all the time with lighting switches hot in switch leg out but no neutral.
That's not an issue if the line and load conductors share a raceway between the switch(es) and the point where they leave and rejoin the grounded conductor(s).

In the OP, it's stated that the line and load conductors do not share a single raceway/conduit/nipple, and the grounded conductor does not follow their pathway.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I don't know if what I am talking about would cause inductive heating either.
Yes, caused by whatever neutral current there might be. Whichever circuit conductor does not either parallel or oppose that of the others is the conductor whose current will be the cause of induced heating current.

Did you follow that? :confused:
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I've been told that soon enough we will be able to do this with all appliances, etc, in the smart home.
Actually, that's easily done, and has been for years. Old-school X-10 and a contactor or RIB for hard-wired stuff is all you need.
 

iMuse97

Senior Member
Location
Chicagoland
Yeah, that's along the lines I was thinking. Like I said, I know this will work but I don't want to give the inspector a reason to fail a job.
The breaker is 50amp and the conductors are #8's. The tap conductor is #12 as well as the grounded conductor to the coil. The #8 grounded conductor is not routed up to the relay box with the others. None of this is UL listed as an assembly (I know you're laughing). This is all easy to build, but it should be just as easy to build to code.

Could an inline fuse work to protect your #12s?
 

CFL

Member
Yes, caused by whatever neutral current there might be. Whichever circuit conductor does not either parallel or oppose that of the others is the conductor whose current will be the cause of induced heating current.

Did you follow that? :confused:

Yeah, I follow. What I should have said was I don't know if my situation would cause enough heating to make any difference. I honestly don't know how much 120v load is on the average range. I do know I couldn't find an exception that would allow me to run the hots without the neutral.
 

CFL

Member
I'm not laughing at all. I often do what you're describing when adding an appliance to be deenergized by an existing Ansul-type kitchen system.

Usually you have a 120v 20amp circuit handy to control your contactor when doing an ansul, correct? That's how I would prefer to do this, especially since the ansul circuit originates in the same panel. I always get the same response when I bring something up, "We've been doing it that way for years, it's never been a problem". I really wonder if I'm just being pain. I find these issues on every job, and every time I'm met with the same response, which is basically, "Just shut up and do the job".
 
Status
Not open for further replies.
Top