Neutral wires and circulators

Steamhead

which were usually 32-volt DC. And it wasn't unusual for a city to have different systems in different areas. Baltimore had both DC and AC systems until about the 1920s.

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Unknown

We work in alot of homes

where one or more thermostat wires come to the boiler powered 110v from the thermostat directly . Rewiring the zones or using relays are always an option . But we'll usually break the main zone through the low limit and hook in the other zones direct to their pumps . But sometimes this aint the best situation with an internal coil in the boiler . Is there any problems with running all the pump zone neutrals through the low limit ? Are there any electrical codes that forbid the practice ? Thanks in advance .

Firedragon_4

NFPA70

the National Electrical Code does not allow anything on the neutral line but a wire nut, FACT! Sorry!

Unknown

Ahh , thanks George

Does it go into detail of why ? After all , it's all a big , happy circuit . I'd guess it has to do with putting someone servicing the unit at more risk of shock ?

Firedragon_4

You got it,

risk of shock and damage to components!

My pleasure,

www.firedragonent.com

Empire_2

control

why would you usually run 110 vac instead of 24 vac? Not only is it a safety factor, but it's easier to run lo voltage cable. Also looks nice to have relay center. Are you are worried about cost?

Firedragon_4

Most of Levittown

and et al is wired that way. Thank gawd they didn't wire many of the Campanelli's that way.

www.firedragonent.com

bill_51

if you've never heard the phrase"don't switch the neutral" then you may find out the hard way when you turn off the power and then grab the supposed neutral wire and a copper pipe...grounded copper pipe that is.......

jim lockard

It anit happy

If the hot is live on the pump and for some reason the ckt goes short to ground and your pump takes off. or any other piece of equiptment. You Privy diggers should know that, ever get wacked by a garbage disposal being switched on the neutral?? Best Wishes J.Lockard

Unknown

Why would I ?

Like I said , the wire comes down to the boiler already powered 110v from the t-stat . I'm there to replace a boiler , not snake thermostat wires up walls . And also like I said , I can knock any line voltage wire to low voltage with a simple relay . This is just a rhetorical question .

Many homes on Long Island have at least one zone that comes to the boiler hot 110v . Like George said , Levittown has tens of thousands of homes like that . The only caveat in those homes is the main zone thermostat breaks the neutral - the existing wire is hot right to the pump . I'm still wondering why they did it that way in the late 40s .

Unknown

Theres a town out east of me

where the emergency switch at the top of the stairs is wired to break the neutrals . I learned real quick to trip the breaker at these homes .

jim lockard

maybe Ron

IN the early days they were use to dealing with "hot lazys " where with both 1pole and 3pole switches in the era of knob and tube wiring they would switch on the neutral. All I can think of. J.Lockard

Steamhead

There was also a circuit

called the "Carter" circuit that used two three-way switches and any number of four-way switches in a hookup that interchanged the hot and neutral. This was used in a lot of rural areas between houses and outbuildings since it required one less wire than the standard circuit to operate. Scary!

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Maine doug

When you

lose a neutral, the 120 voltage can be seen as 220 in some circuits. Once we lost a neutral in a series of office cubes. Everything on that circuit started smoking. Not a good thing to do.

Mike T., Swampeast MO

Old knob-and-tube lighting circuits most often switched the neutral. Have never understood why other than the remote possibility that faults that occur over time will often appear as a light that flickers on and off without touching the switch.

Steamhead

According to an electrician I knew years ago

who is now a Dead Man, in the early days of wiring there was no polarity or grounded neutral as we now know it. 60 volts on either side of the line added up to 120 volts, and you only had to break one side of the circuit to turn off the light. This is also the reason many old fuseboxes have fuses in what is now the neutral side as well as the hot side.

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oil-2-4-6-gas

i have been "bit" by 2 boilers wired switching the nuetral -i was testing the way i was taught -110v test hot to nuetral ----you think i would have learned after the first 1 --------of course i have since tested all wires to ground seperate the best 1 is when the power is bx or romex and the hot was the white wire ---neutral is always white but white's not always neutral ---i still find 90% of burner wiring,control and motor not grounded in both commercial and residential ---when we learn ---

jim lockard

Lets see

Mike if I can draw the picture with words. you take a 3way switch on the 2 traveler connections you connect hot to one and neutral to the other. Then at the point (common ) connection of the switch you connect one wire and run it to one side of your light fixture you do the same with the other 3 way switch and run one wire to the opposet side of your light fixture. when you flip the switch you get light with the hot and neutral flip/flopping as you move the switch.

Steamhead

That's right, Jim

Here are two variations of the Carter circuit, found in a 1929 Audel Practical Electricity book, written by Frank Graham. It works by connecting each end of the light to either side of the line. The light only comes on when one end is connected to one side of the line and the other to the opposite side.

Note to everyone reading this: Do NOT wire your switches this way. This circuit does not meet Code, and hasn't since at least the 1940s. Two reasons are that what is now the neutral wire has a switch in it, and the polarity at the light is reversed depending on how the switches are thrown.

If you come across a (non-Carter) circuit that has the switching in the neutral, as I did in my house, the cure is to reverse the circuit's polarity. If you do this, make sure the polarity is correct in all parts of the circuit.

BTW, the book doesn't say who Carter was.

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Boiler Guy

A little off topic

BUT For years many manufacturers used neutral switching. One I am most familiar with was Lennox. Trying to find a bad or grounded, switched neutral in a rooftop AHU control cabinet while freezing your butt in the middle of winter was an all too common experience. Moisture and high humidity conditions in summer made the challenge even more fun. Getting slaps off the improperly grounded water pipe helped put a spring in the step of many a service person.
Ahhh the "good ole days".

Dale

Interesting discussion

Where I live in the old days the neutrals were fused, called storm fuses. This is where a 120V service was brought into the side of the house and a fuse box was in the attic or upstairs hall. Service man finds 120 to ground but not to neutral, very dangerous. Maybe that's were the neutral switching comes in. One point, the NEC ends at the appliance,some manufacturers do break the neutral inside the appliance, common in dryers and fridges. I think also that it's good at this point to remember that the NEC calls the neutral the "grounded conductor" emphasis on conductor. And the only place it can now be tied to ground is at the entrance panel. I fix ALOT of "getting a shock when I touch the xxxx" problems by separating the grounds and neutrals and insulating the neutrals at SUB panels. If you see 120V thermostats now I wonder how much it would cost to change them to 24 volts. The thermostat wire doesn't care, or more correctly doesn't need to be changed, if you go down in voltage and that way the connections will be easy and safer for those who follow.

Boiler Guy

Check out wiring question thread too

jim lockard

hey mike

Steamheads got the picture. J.Lockard

jim lockard

Please remember that

THE NEUTRAL carrys the same amps as the "fire wire" and in some cases more. should you get caught in between neutrals you can be by by real quick. J.Lockard

Unknown

Jim , they built these homes ......... cheaply ?

At least as far as the boiler wiring goes . We find most of them have a single 3 wire romex coming from the emergency switch at the stairs to the boiler . Black is power for the boiler , white is neutral and red is power from the thermostat . No ground wire . Most homes out here were built in the late 40s through the 60s .

Tharon

Hey Ron

technically speaking if you have only two wires, you have a hot and a ground, you actually need three wires on a 120v circuit to have a nuetral. Many service men confuse the neutral and ground. Just my two cents worth



Peace Be With You


David C. Broome

Mad Dog_2

Yep...a litlle knowledge is a dangerous thing

I once had a guy tell me that "the white wire can't hurt ya...its got no juice in it!" Its meant for bozos like that. Mad Dog

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Unknown

Technically speaking

I thought a ground is there for protection of electrical shock , and the neutral is used to complete the circuit ? If there's only a black and white wire , isn't the white considered neutral if it goes to the ground bar in the circuit panel ? What am I missing ?

The Wire Nut

Polarity...

As there are polarity markings it looks like these have been designed for some sort of DC system. I know there used to be a lot of DC in the early days (hence the old AC/DC radio/appliance...ah the days of the 5 tube AM super-het radio...) and perhaps these were meant for lower voltage...

DC disappeared as it was impractical and expensive to deliver and was more dangerous then AC. Electric chairs are DC by the way...

Also, in the old days outlets were 2 prong, non-polarized. There was no way to assure that the switch was on the hot or the neutral in the appliance. After enough people get hurt, things change. First to polarized plugs and finally to 3 prong...

Steamhead

You have it right, Ron

NEC calls it the "grounded" conductor. But it's also known as a neutral since it normally carries current but does not have (or should not have) any voltage on it. The green (or bare) wire is called the "grounding" conductor since its job is to ground the equipment, and does not carry current unless there is a "ground fault" which is a short circuit to ground.

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Unknown

You're right Matt

Thinking the white wire aint got no power in it ....

I found out the shocking way that Levitt had some creative thinkers to wire his homes . I changed the light fixture in the kitchen , hit the breakers till the old light went out . Took the neutrals apart and saw a spark . The boys who built the house made the light fixture a junction box for another live neutral , on another circuit altogether . That can't be good carrying more than one breaker's neutral on one 14 gauge wire , can it ?