Electrical wiring of emergency shut off switches

Squidstro · July 3

When I had my gas boiler replaced in 2016, the 110 VAC single pole switch that supplies power to the furnace was malfunctioning. Probably because it was 36 years old and in a damp and dusty utility room and was rarely used in its service life. Nevertheless, the plumber got a replacement single pole switch and replaced it. Of course he messed up the wiring because the box had extra wires in it and he got confused. He assumed it was a simple box with the load and line wiring and that's it. But it turns out my house has 2 switches to turn off the furnace. One is upstairs in a foyer. The other is right next to the furnace (the switch I'm talking about that he replaced).

So he got it wired to properly switch power to the boiler, but the upstairs switch became useless and now I want to fix it.

I haven't opened both switch boxes yet, but since the original switch was a single pole switch and not a 3-way, I'm assuming the builder who built this house put these 2 switches in a sequence so that both need to be in the on position for the furnace to get power.

So assuming where the line power is, this is how I plan on wiring the 2 switches with the furnace. First, if the line power is coming into the upstairs switch, then I will wire the sequence like this:

However, if the line power is coming into the downstairs switch (which I think it is) I will wire the sequence like this:

My questions to this community are:
1) Is it normal to have two switches on a boiler circuit setup with two single-pole switches in sequence? Why don't they use 3-way wiring? Code? The house was new construction in 1980 in northern New Jersey if you're wondering.

2) If my wiring diagrams are sound, I have two low voltage transformers to wire into that downstairs switch box. The thermostat transformer and a doorbell transformer. What are my options on wiring them in this following diagram:

Ideally I would like the thermostat transformer to shut off with the boiler. But I'd like the doorbell transformer to stay on. If that's not possible, then it's ok for the doorbell transformer to shut off with the boiler and everything else.

Thanks for your help in advance!

Fred · July 3

It is fairly common to have two switches to shut a boiler down, One typically at the boiler, the other usually at the top of the stairs or somewhere else. You need a three way switch so that either switch can function (on and Off) independent of the other.

EBEBRATT-Ed · July 3

Your wiring diagrams are correct. Good job. If you use any white wires for the hot part of the circuit mark them with a black sharpie pen or with black tape. That wasn't required in 1980 but is a good idea. It is normal with 2 switches to put 2 single pole switches in series like your drawing shows.

You don't want to use 3 ways. Someone could be working on the boiler and the person upstairs could start it up causing a dangerous situation

I would mount the boiler transformer on the boiler itself. It's probably easier than on the service switch unless the switch is on the boiler. Killing this transformer with the service switch is ok.

I would find a different circuit to put the doorbell transformer on. That way you will always have door bells. No need for a switch to shut that transformer off it can be live all the time. Just open the circuit breaker or pull the fuse to work on it

Squidstro · July 3

Fred said:
It is fairly common to have two switches to shut a boiler down, One typically at the boiler, the other usually at the top of the stairs or somewhere else. You need a three way switch so that either switch can function (on and Off) independent of the other.

Fred, my original builder put single pole switches. You don't think my diagrams are sound? You can't put two single pole switches in a sequence?

A 3-way switch would be able to have power to the boiler with both switches in the down position and both switches in the up position. That doesn't sound like it's something code would want for "emergency shut off" switches that are explicitly labeled by direction with these plates:

STEVEusaPA · July 3

The doorbell transformer should not be on the same circuit as the boiler. The boiler needs to be on it's own circuit. The thermostat transformer can be mounted to the box on the disconnect at the boiler, in parallel.

Safeties are always wired in series. You can't do a 3 way as someone could be working on the unit at the unit with the switch shut off, and somewhere else in the house, someone could flip the switch back on. Dangerous at best, deadly at worse.

You need a disconnect at the boiler to be within reach for the tech.
You need another disconnect outside the room of the boiler, in case of emergency (fire, sparking, etc.) you don't have to go to the boiler to shut it off.
And now that you touched it, you probably need a thermal disconnect above the boiler on the ceiling, also wired in series.
So 3 in series.

Squidstro · July 3

STEVEusaPA said:

And now that you touched it, you probably need a thermal disconnect above the boiler on the ceiling, also wired in series.
So 3 in series.

That's a good idea. I hear runaway boiler calls on my police scanner all the time. Seems like a great defense. I didn't even know about thermal disconnects until now. Thanks STEVEusaPA.

lchmb · July 3

for a period of time in NH we were required to remove the upstairs switch. It may be that he did this and failed to mention it, although we always remove the switch as well

Jamie Hall · July 3

What @EBEBRATT-Ed said. As usual...

Squidstro · July 3

lchmb said:
for a period of time in NH we were required to remove the upstairs switch. It may be that he did this and failed to mention it, although we always remove the switch as well

Ichmb, this guy was a clown. Trust me. He messed up. He also killed the doorbell too and we had to troubleshoot it. He shouldn't have even been working on electrical components because he's not a licensed electrician. He's a plumber. But they dabble in the shut off switches because it's tightly integrated with HVAC work. He knows electricity well enough. But it was an oversight on his part that the switch was part of a 2 switch sequence. He was hasteful and careless. Frankly, all he had to do was label the wires when he removed the original switch before he installed the replacement switch. But he ripped that original switch out - went to Home Depot for the replacement - and when he installed it, didn't remember the wiring correctly. I have to go look at that new switch. He may have even bought a 3-way. He was that sloppy.

He didn't even diagnose the original malfunction correctly. His boss came and diagnosed it after he fried 2 brand new control boards on the new furnace from the arcing.

I didn't know he was problematic until he blew the 2 control boards. Then I had to get involved and micromanage his work (which no homeowner wants to do). That install had so many issues:
1) Two brand new control boards fried due to the arcing switch. I had to wait for two FedEx overnight's from Slant-Fin. One was over a weekend. It was February in New Jersey. The owner had to lend me some space heaters. The 3rd control board is in that new boiler.
2) He installed the water pump backwards. The zones were doing hard water hammers when the zone valves shut off. I had to call him back and get him to reverse the water pump to the proper direction.
3) The topic of this forum. He messed up the original builder's wiring of the two sequence switches. My doorbell was offline. After we got the doorbell back online and had the boiler switch working, I let him go. I didn't want him doing any more damage. I knew I would fix those switches myself.
4) The switch arcing burnt out both of my thermostats. He tried to charge me for replacement ones. He had tons of trouble getting the two zones wired properly with the honeywell zone valves because he was unaware that the thermostats were blown so he was trying all this unnecessary troubleshooting. I caught him trying to leave one zone valve open in maintenance since he could't get that zone to work with the thermostat. So basically one zone was calling for heat on both always. He played dumb on that.
5) The water pressure reducing valve he installed on my water feed was faulty. It wasn't regulating under 15 PSI. So the overflow was spewing water all over my utility room. He put a bucket to catch it. He tried to blame the city water pressure being too high. I had to deal with that nonsense argument too. He went and got a new one from the plumbing supply store and it worked fine.

Steamhead · July 4

lchmb said:
for a period of time in NH we were required to remove the upstairs switch. It may be that he did this and failed to mention it, although we always remove the switch as well

Inspectors around here now want emergency switches for gas- as well as oil-fired boilers. They're a good idea even if not required.

EBEBRATT-Ed · July 4

@lchmb ,
Can't fathom what reasoning NH would require emergency switches removed. True, they sometime cause nuisance no heat calls but the +++ oughtweigh the- in my opinion.

@Steamhead
MA has required emergency switches "outside" the boiler room forever on oil. They wont accept the top of the stairs on the basement side of the door. People used to hide them upstairs (I have seen them in closets which defeats the purpose) now they had changed that so they had to be in plain sight...but that was MA code which they did away with 4 years ago and now adopted NFPA 31 to save money... not sure what they require.

Gas never required them on residential or commercial. But I think it's ASME CSD-1 that requires them now on gas and oil....and they want them at every boiler room entrance...if there are multiple entrances.

The ASME thing only started in the last 5 years around here but enforcement is hit or miss. Fire dept inspects oil here and doesn't know ASME. Gas inspection by plumbing inspectros and they don't know ASME either. But a new commercial boiler with a state inspection they will pick up on it.

@Jamie Hall
When I worked in Hartford years ago I saw a lot of residential jobs with a switch inside the stair well going to the basement at the top of the stairs....but no switch at the boiler....must have been a hold over from the old days, these were all older jobs. Was a PITA to work on the burners. Pulling a stat wire off the old stack switch to start & stop and test burner. Bleeding an oil pump was exciting!!

lchmb · July 5

EBEBRATT-Ed the theory was if the unit malfunctioned, they wanted the internal safeties to be able to function (inducer motor, blower motor) and not have the customer shut it off. The gentleman in charge at the time stated the code required an uninterrupted line from the panel to the unit.. then they said we could leave them but not required to install them... at this point I'm honestly not sure what they want..

Squidstro · July 6

I opened my switches. The power is definitely going to the 1st floor switch. There's also a junction box between the switch and the furnace (I guess to hold the transformers). Here is a pic:

I'll try to move my doorbell transformer somewhere else, but the 18 gauge doorbell wire is routed to that area with the intent to be on the same circuit as the furnace. There's a different circuit in that utility room where I could consider moving the doorbell to.

Here is an updated diagram on how I plan to fix the wiring:

I'll test the switches with a light fixture or my multimeter with the furnace out of the equation to make sure all the switching is working the way I want it to. Then I'll wire in the furnace last.

I'm also going to change the plain switch plates to put those red emergency shutoff plates for safety.

HVACNUT · July 6

The diagram is perfect.
Technically the heating system(s) must be on a dedicated circuit. But the old doorbell piggyback has been around for years and draws really nothing unless kids constantly play Ring n Run by you and the chime plays a full concerto.

Squidstro · July 6

HVACNUT said:
The diagram is perfect.

Technically the heating system(s) must be on a dedicated circuit. But the old doorbell piggyback has been around for years and draws really nothing unless kids constantly play Ring n Run by you and the chime plays a full concerto.

Well now I have a Ring® Video Doorbell which needs full time voltage from the doorbell transformer. I also would like the ability to kill the power to the doorbell transformer for maintenance without affecting the furnace. That doorbell transformer in the photo is super old and buzzing somewhat. So I’m afraid it had something to do with the faulting of the original super old switch. Another reason I don’t want the doorbell transformer wired into this junction box.

STEVEusaPA · July 6

Side note: What are you using to drawing these diagrams?

Squidstro · July 6

STEVEusaPA said:
Side note: What are you using to drawing these diagrams?

Haha. You like my diagrams, don't you?

I come from a background in graphics design and IT solutions design. For these diagrams, I used a little Photoshop and Visio.

The switch plates, furnace, switches, transformer, service panel and wire nuts are all images from the internet. The rest is Visio.

EBEBRATT-Ed · July 6

Love Visio, not that I am very good with it

Squidstro · July 6

EBEBRATT-Ed said:
Love Visio, not that I am very good with it

It's expensive. Luckily I have an older licensed version. Visio is all about the billions of shapes for professional drawings, designs and plans. I just used basic shapes for these drawings and stole a bunch of images from the web as more objects to use. There are plenty of free design generators out there but you have to find them and learn their quirks.

But it takes years of practice from being in the field. Visio didn't magically throw that together for me as a template. I had to take my time deciding on the layout and reworking things. It took hours, not minutes. But it's a hobby of mine and I have fun doing it.

EBEBRATT-Ed · July 7

@Squidstro
My Visio is a few years old. I bought the cheapest version but then found everything I added to it works. I have done some decent prints with it....nothing fancy. Now that I can use it a little it's fun. Learning was very frustrating

Condoman · July 7

No one mentions here but when I see an upstairs switch I always recommend that they put a switch guard on it. More than once I have been in a home where the owner or someone else turned off the basement lights (sometimes without even looking) and it was the upstairs they actually turned off.

The next day when they are cold or no DHW it is not remembered. Call to service tech $$$ are gone and you as the HO are embarrassed.

For us it is a joke because the HO did exactly that on one New Years Eve and the new year was off to a very cold start in RI.

Squidstro · July 7

Condoman said:
No one mentions here but when I see an upstairs switch I always recommend that they put a switch guard on it.

That's why I'm going to use the red warning switch plates. For "normal" people to know what they'll do. I also have a switch guard because I live with someone with late stage Alzheimer's Disease.

Although, I have this one:

It will probably block most of the print on the emergency shut off switch plates. So I should see if some clear ones would be better.

EBEBRATT-Ed · July 11

Sometimes mounting them high on the wall will help deter accedential shut down

HomerJSmith · July 11

I'm having a dumb day, today. Why would you want to switch the boiler off from two locations? Going down to the basement to switch off the boiler too much effort? One could switch off the boiler at the panel. Oh wait, none of the breakers are labeled.

ratio · July 11

I think it's more of an 'Oh Sh!t, it's on fire!' kind of thing, where you might not want to get any closer than you already are.

Jamie Hall · July 11

You want one in the basement -- not far, but far enough -- to use when you are working on the boiler. The other one is for @ratio 's contingency...

STEVEusaPA · July 11

Stated earlier...

STEVEusaPA said:
...You need a disconnect at the boiler to be within reach for the tech.
You need another disconnect outside the room of the boiler, in case of emergency (fire, sparking, etc.) you don't have to go to the boiler to shut it off...

HomerJSmith · July 11

Hmmm, really Fire??? Hows shutting off the power going to stop a fire? And of course there are no circuit breakers outside where it is safe to shut off the electricity. It's probably better to have a fire extinguisher rated for electricity handy with a gas meter wrench next to the meter. There must have been a reason for it.

STEAM DOCTOR · July 11

> @HomerJSmith said:
> Hmmm, really Fire??? Hows shutting off the power going to stop a fire? And of course there are no circuit breakers outside where it is safe to shut off the electricity. It's probably better to have a fire extinguisher rated for electricity handy with a gas meter wrench next to the meter. There must have been a reason for it.

Shutting power should close the boiler gas valve

HomerJSmith · July 11

Yes, but I assume the gas valve isn't functioning properly if there is a fire. Excessive gas pressure, etc. or the fire before the appliance gas valve.

HomerJSmith · July 11

Squidstro, sez
"So he got it wired to properly switch power to the boiler, but the upstairs switch became useless and now I want to fix it."

The wiring isn't as depicted in your first diagram or else the top switch would work if the boiler switch works as the power is coming thru the top switch. But....The power is coming in at the boiler switch and you have a 2 conductor romex cable going to the top switch, I think. The second diagram is the sensible way to wire it. The transformers would always have power, not switched power. It all depends on where the power comes in.

STEVEusaPA · July 11

@HomerJSmith ...or shut off the oil burner...or any other reason where it’s not safe to go to the appliance or get to the panel.
I’m telling you what the code says, for safety and probably enacted because of 1 or more specific tragedies.
You can do what you want.

HomerJSmith · July 11

All the residence and many were built in the early '30's that I have come across had a service entrance panel on the outside of the building that would cut electricity to the building even if there was a sub panel in the basement or utility room in view of the boiler that may be inaccessible because of fire, that electricity could be disconnected.

I'm not saying (two boiler disconnects) whether it's a good idea or not, but the logical reason for it. I know, the code is at times unreasonable. But, the NEC is written in legalese and consistently reasonable. I mean, if you have two disconnects, three would be better, don't you think.

As my memory bordering on Alzheimer serves me, one can hard wire a boiler or furnace without a disconnect into a circuit as long as the breaker controlling that circuit is in a panel that is a viewable distance from that appliance.

Jamie Hall · July 12

Yeah, @HomerJSmith -- when we had some rewiring done at Cedric's home we had to put in an outside disconnect breaker per code. Never mind the main disconnect under the porch 3 feet away -- 200 amp -- which was wired with a separate auxiliary disconnect for the pump. Result: if there were a fire, the first thing they'd do is kill the outside disconnect. Brilliant. Then the sprinklers in the hay barns and the hydrants in the main building would shut off when the pump did. Get out the marshmallows and hot dogs and let 'er go.

When I was a building inspector, I always tried to use common sense, not book l'arnin'. Not any more...

EBEBRATT-Ed · July 12

Any motor driven appliance is required to have a disconnecting means in site of the motor and less than 50 feet away. (boiler and furnace codes usually require one at furnace)

Some motor driven appliances (garbage disposals and dishwashers) never had disconnects in the past but they are now required.

"emergency switches" for oil and gas furnaces and boilers just make sense, they are not NEC required but may be required by boiler and furnace codes

Squidstro · July 20

HomerJSmith said:
The wiring isn't as depicted in your first diagram or else the top switch would work if the boiler switch works as the power is coming thru the top switch.

The diagrams are how I am going to fix it. I confirmed the line power is entering at the downstairs switch box. So the second diagram is the way I want to fix it. I didn't diagram the plumber's mistake anywhere in this post. When he replaced the downstairs switch, he didn't realize it was part of a 2 switch sequence. So he wired it to get it working by itself and was confused by the extra wires and probably capped them. The way it stands today, the upstairs switch is dead. The downstairs switch works.

During his time on the job, I didn't have the time to troubleshoot his work. I wasn't hovering. It took me a while to realize he was making a lot of mistakes a professional shouldn't make. I cut him loose and didn't want him making anymore mistakes. I knew I'd fix these sequence switches myself when I got the time and patience.

ChrisJ · July 20

> @HomerJSmith said:
> Hmmm, really Fire??? Hows shutting off the power going to stop a fire? And of course there are no circuit breakers outside where it is safe to shut off the electricity. It's probably better to have a fire extinguisher rated for electricity handy with a gas meter wrench next to the meter. There must have been a reason for it.

Are you a contractor?

Steamhead · July 20

ChrisJ said:
> @HomerJSmith said:

> Hmmm, really Fire??? Hows shutting off the power going to stop a fire? And of course there are no circuit breakers outside where it is safe to shut off the electricity. It's probably better to have a fire extinguisher rated for electricity handy with a gas meter wrench next to the meter. There must have been a reason for it.

Are you a contractor?

Read your history. Some of the original oil burner designs were scary by today's standards, and did cause fires. So Codes began requiring emergency switches to be installed at the entrance to the boiler or furnace room, so you could shut off power without approaching the unit.

This is yet another illustration of the old saying that Codes are written in blood.

EBEBRATT-Ed · July 21

Had one where the homeowner stored tin cans and beer bottles to be recycled in paper shopping bags piled around the boiler. This was a old "snowman" boiler with a Gilbert & Barker burner. Old Webster model "W" pump and the pump cutoff failed. Oil leaked onto the hot blast tube and ran out on the floor burning, lighting the paper bags. Luckley the oil firomatic valve and the overhead electrical firomatic shut it down and save this 1800s house

Electrical wiring of emergency shut off switches

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