Can my vintage boiler wiring be updated to modern wiring?

So I googed "Knife Switch" and looked at images that were all very much like the one on the right.

@mattmia2, can you explain how the one on the left is not a knife switch? Does the enclosure make this not work the same way as a knife switch? Does the handle need to be that piece of bakelite of rubber or some other insulating material at the end you lift to open the circuit? I thing this Square D enclosed fused disconnect uses two knife switches in the assembly. But I might be mistaken. I want to be accurate when explaining the facts.

old electrical switch gear

These are knife switches

I knew what he meant as well.

a knife switch is open, it isn't enclosed. almost any high current switch's contacts are going to be a bar of metal moving in any out of a pair of contacts, usually rotating on a shaft like in that enclosed safety switch, even high voltage transmission line switches have similar contacts. that contact arrangement in itself doesn't make it a knife switch. you could have a knife switch in an enclosure but in a knife switch you are moving the contact bar directly, usually with an insulated handle on the end of the bar, it isn't moved from outside of the enclosure with a remote handle.

square d made their business selling that switch as a safe replacement for knife switches.

a lot of old theater lighting systems were open slate boards with open knife switches to route the crosspoints to/from the dimmers and open dimmers.

Yes that is amusing.

To me a knife switch is a basic style of switch. If you enhance the application of it by putting it in an enclosure and that may also include mechanical interlocks, etc. and you call it a safety switch that is fine too.

To me the knife switch part is often a sub-assembly of a safety switch.

I have a boiler that actually boils water to make steam. All you hot water folks have something else, I just don't know what to call it. Apparently no one else does either so they call it a boiler. And if water is boiling inside that is BAD.

Deserve… I thrive on this type of stuff.

Thanks for your support Chris

and all refrigerators are Frigidaire

How dare you!!! We don't use the F word in my house.

@ChrisJ

My mistake. All refrigerators are😎 GE

The way I see it, if you want you can shut off the pilot in the summer. IMO Thermocouples are inexpensive and maybe more reliable than Intermittent Pilot ignition modules. For me I'd rather have the reliability when it is cold out. And yes you could have a spare of either, but the Intermittent Pilot ignition module will cost a lot more.

And many that don't. I don't want to find out when it is zero outside on a weekend. I like my heating as simple as possible. It is your choice… I my case, have no desire to replace my old boiler or any of its controls just because I can. To me new is not necessarily better.

In @TheUpNorthState88's case replacing the boiler's control wiring is a reasonable idea. It provides an opportunity for him to learn the system better, improves the quality of the wiring and to remove unused abandoned equipment. Removing the electrical clutter makes it easier should the system ever need service in the cold of the Winter.

IMO he does need the right person to do the job. I'd hate to hear that an electrician ripped it apart, got confused and then walked away, or an HVAC contractor just wants to sell a new boiler.

What's bad about it? Assuming the hot is switched with it I mean.

I'm sorry, you said switching not fusing, so I went off of that.

the 2 pole switch is ok but unnecessary, the fuses are the problem. maybe try a penny….

LOL

Yeah > like > until someone does you a "favor" > fur sure > and puts a fuse in there for you. Like maybe a 10 amp fuse while the hot has a 20 amp fuse. They heard that putting a penny in those fuse holders was a No No!

It's the same as the neighbor closing a basement window while he was watching your house, while you went skiing for a week in Aspen. You come home to a sooty mess because of that favor that shut off all the combustion air. That is why you need to follow the code. A permanent combustion air inlet is required, not an open window that can be closed by your friend.

I could give you hundreds of "Good Enough" fixes, just like those examples, that would not pass a code inspection. Just do it right!

(NEC 404.2) Only the ungrounded (hot) conductor may be switched.
A grounded (neutral) conductor shall not be connected to a switch unless the switch is listed and identified for that purpose.

So why is there any discussion on this topic. I was taught that rule over 50 years ago. Of course there are exceptions to that rule but a gas burner in your basement is not one of those exceptions! Don't do it! Fix it if you find it. or have the customer call an electrician to fix it if you find it. Note it on your work order. That way you are not liable if something comes up about it later.

Sorry I'm retired. and my wheelchair probably can't get down that basement.

The disconnect switch(which can be an ordinary toggle switch) and the transformer are the only parts that need to be protected. The rest could be replaced with modern thermostat wire dressed with zip ties and anchors and bushings.

If it were mine I would bring a new dedicated circuit(code requirement, the load is tiny) in to a new switch and transformer, remove all the existing wiring keeping the t-stat wire and wire all the controls and safeties in series from that new transformer to the gas valve with new t-stat wire using bushings/grommets in the various controls where the loom/bx/flex connects now and adding anchor points as needed.

Some of the safeties are switching line voltage I think because it had an oil burner at some point. Those can be moved to the 24vac circuit.

You should also rebuild the lwco if it hasn't been apart in a while.

It has already been reworked several times and has remnants of old things that are no longer there hanging around.

This is what the michigan residential code says about switching neutrals:

E4001.8 Grounded Conductors

Switches or circuit breakers shall not disconnect the grounded conductor of a circuit except where the switch or circuit breaker simultaneously disconnects all conductors of the circuit. [404.2(B)]