What Kind Of Cable Was This?

This is what I got:
"Remote-control circuits for a oil burner safety-control switch are classified as a Class 1 Safety-Control since the failure of the switch to operate introduces a direct fire or life hazard.
As covered in 527 CMR 12.00 Massachusetts Electrical Code (Effective 2/17/23) NFPA 70 NEC Section 724.31, all conductors of such remote-control circuits shall be installed in Type MC cable or one of the other wiring methods listed in 724.31, NM cable is not suitable for this purpose".
 
Maybe a typo?

ARTICLE 725
Class 1, Class 2, and Class 3 Remote-Control,
Signaling, and Power-Limited Circuits

725.31 Safety-Control Equipment.
(A) Remote-Control Circuits. Remote-control circuits
for safety-control equipment shall be classified as Class 1
if the failure of the equipment to operate introduces a direct
fire or life hazard. Room thermostats, water temperature regulating
devices, and similar controls used in conjunction with
electrically controlled household heating and air conditioning
shall not be considered safety-control equipment.
(B) Physical Protection. Where damage to remote-control
circuits of safety-control equipment would introduce a hazard,
as covered in 725 .31 (A), all conductors of such remotecontrol
circuits shall be inst:illect in rigid metal conduit,
intermediate metal conduit, rigid nonmetallic conduit, electrical
metallic tubing, Type MI cable, or Type MC cable, or be
otherwise suitably protected from physical damage.
 
pipe_bender said:
Yeah ok interesting thanks for the clarification.
I only mentioned that because I just got dinged Friday in a town I don't usually work in, it was a old oil burner switch I moved, it was BX that I yarded out, at the top of a basement stairs during a remodel.
They replaced and widened the stairwell so I ran new NM cable.
The inspector emailed me that the code section was "2023 NEC section 724.31 and 725.31 in the older code books." i did not fight him on it as I am not familiar with these.
Click to expand...
That's a new one unless it is some local thing
 
pipe_bender said:
The one thing it does not work on is occupancy sensors, I have burned up about a dozen occupancy sensors when I switched out toggle switches to sensors in a large office building wired with the old BX.
Click to expand...
That's very interesting. I would want to know why that happened. I understand that some occupancy sensors (and dimmers) use the EG when there is no neutral in the box. Perhaps that has something to do with it.

-Hal
 
pipe_bender said:
This is what I got:
"Remote-control circuits for a oil burner safety-control switch are classified as a Class 1 Safety-Control since the failure of the switch to operate introduces a direct fire or life hazard.
As covered in 527 CMR 12.00 Massachusetts Electrical Code (Effective 2/17/23) NFPA 70 NEC Section 724.31, all conductors of such remote-control circuits shall be installed in Type MC cable or one of the other wiring methods listed in 724.31, NM cable is not suitable for this purpose".
Click to expand...
Doesn't the switch just control the branch circuit feeding the oil burner?
 
Seems kind of funny, Oil burners made in recent years have flexible cord something like SO for wiring the boiler/furnace
 
readydave8 said:
Just in the last 2-3 years I realized I don't have to say "with ground" at supply house

When I started (late 70s) we would often have both on job, since switches and lights didn't need a ground
Click to expand...
Yes. All receptacles needed EGCs sometime in early 60's I think, and may been a time where certain ones required an EGC but not all of them before then. But there were still other items that didn't require an EGC until several years later and cable with no EGC was still available until the demand for it simply went away.
 
hbiss said:
Yes. I guess they are worried that the wiring needs to have some survivability in case there is a fire and allowing someone to turn the oil burner off. NM wouldn't take long to melt shorting the conductors together and rendering the switch useless.

-Hal
Click to expand...
I wonder why it's only required for oil. I don't think gas needs it, and I know the coal stokers we use around here don't
 
Joethemechanic said:
I wonder why it's only required for oil. I don't think gas needs it, and I know the coal stokers we use around here don't
Click to expand...
I think because oil tanks are often in the same room as the boiler, while gas usually has an external shut off point and bulk coal ignition is not typically as fast as liquids and gas.
 
infinity said:
Doesn't the switch just control the branch circuit feeding the oil burner?
Click to expand...

hbiss said:
Yes. I guess they are worried that the wiring needs to have some survivability in case there is a fire and allowing someone to turn the oil burner off. NM wouldn't take long to melt shorting the conductors together and rendering the switch useless.

-Hal
Click to expand...
If the switch controls the branch circuit then how is it a Class 1 circuit?
 
infinity said:
9

If the switch controls the branch circuit then how is it a Class 1 circuit?
Click to expand...
In MA they consider that oil burner switch as a remote-control circuit for safety-control equipment, so then
since the failure of the equipment to operate introduces a direct fire or life hazard it "shall be classified as Class 1"
When I asked the inspector for some more info he sent this:
In MA the current requirement for that switch is in NFPA 31 10.5.1.1:
For electrically powered appliances, the requirement of 10.5.1 shall be accomplished by an identified switch in the burner supply circuit, placed outside of and adjacent to the entrance to the room where the appliance is located. The switch wiring falls under NEC 724.31 Safety-Control Equipment.

The old requirement before 2015 was in MA, 527 CMR 4.00 section 4.04 (3)(a):

"The valve or switch shall be plainly marked to indicate it's purpose and placed outside the entrance to the room where the burner is locate or outside of the cellar/basement door at first floor level in an exposed location clearly visible and readable at all times."
The old requirement for the wiring to the switch was under NEC 725.31 Safety-Control Equipment.
Click to expand...
 
jim dungar said:
bulk coal ignition is not typically as fast as liquids and gas.
Click to expand...
Yeah, the anthracite we burn (Typically Rice) in our stokers is hard to ignite. You have to start a wood fire and then put coal on the fire. If it doesn't have a good draft it tends to go out. We have a "keep fire" timer in the control circuit that periodically starts the combustion air blower and the coal feed for a short run. I have a real good draft here and my fire will go like 10 hours between runs without going out. But that isn't typical, most need a short run every hour or two
 
pipe_bender said:
In MA they consider that oil burner switch as a remote-control circuit for safety-control equipment, so then
since the failure of the equipment to operate introduces a direct fire or life hazard it "shall be classified as Class 1"
When I asked the inspector for some more info he sent this:
Click to expand...
In MA the current requirement for that switch is in NFPA 31 10.5.1.1:
For electrically powered appliances, the requirement of 10.5.1 shall be accomplished by an identified switch in the burner supply circuit, placed outside of and adjacent to the entrance to the room where the appliance is located. The switch wiring falls under NEC 724.31 Safety-Control Equipment.

The old requirement before 2015 was in MA, 527 CMR 4.00 section 4.04 (3)(a):

"The valve or switch shall be plainly marked to indicate it's purpose and placed outside the entrance to the room where the burner is locate or outside of the cellar/basement door at first floor level in an exposed location clearly visible and readable at all times."
The old requirement for the wiring to the switch was under NEC 725.31 Safety-Control Equipment.
Click to expand...
I'm still not wrapping my head around how a switch in the branch circuit falls under 725.31. Where is the Class 1 safety control equipment in that scenario?
 
infinity said:
I'm still not wrapping my head around how a switch in the branch circuit falls under 725.31. Where is the Class 1 safety control equipment in that scenario?
Click to expand...
I said the same thing to the guy so he kindly emailed me that info, he is a older inspector, usually easy going and clearly has a HVAC background, according him a oil burner switch is a safety-control.
The circuit then is for a safety-control since its a safety-control required by NFPA 31.
I'll get this inspector often in my new route and it was a quick fix so I just fixed it and moved on.
 
pipe_bender said:
I said the same thing to the guy so he kindly emailed me that info, he is a older inspector, usually easy going and clearly has a HVAC background, according him a oil burner switch is a safety-control.
The circuit then is for a safety-control since its a safety-control required by NFPA 31.
I'll get this inspector often in my new route and it was a quick fix so I just fixed it and moved on.
Click to expand...
They're free to adopt and enforce the specific wiring methods as they see fit but IMO they're incorrect in citing that code section as being applicable when you have a toggle switch in the branch circuit.
 
Joethemechanic said:
I wonder why it's only required for oil. I don't think gas needs it,
Click to expand...
I don't know why they consider oil so dangerous. A boiler, if it loses water and there is no low water cutoff can overheat and explode. You would want to be able to switch it off from a safe distance. But that can also happen if gas fired. I can't see much happening with an oil fired or gas fired furnace except it catching fire.

An oil tank in the basement isn't much of a hazard.

As for an emergency shutoff switch for gas, my understanding is that if you smell gas they want you to get out, not flip a switch that could cause a spark. Matter of fact there are some locations that specifically prohibit gas emergency switches for that reason.

-Hal
 
infinity said:
They're free to adopt and enforce the specific wiring methods as they see fit but IMO they're incorrect in citing that code section as being applicable when you have a toggle switch in the branch circuit.
Click to expand...
he must not be the only one because if you look in the old 2017 code handbook its the example in exhibit 725.3 :
Typical installation of an automatic oil burner unit for a boiler employing a safety shutdown circuit required to be Class 1.
1754412107575.png
 
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