ECN Forum Forums Code Related Discussion NEC & other Code issues Heater-Fan-Lite Combos

How do you guys wire Heater-Fan-Lite Combos in Homes? (3 separate functions and controls)

What type of cables do you use and how are they used? What are the options?

Bill

Most of the heat-fan-light combos I have installed also have a nite lite so they are 4 function. They are mostlyNutone brand and come with switches that are back stab only-no screw terminals. I never use the supplied switches. As for wiring them, using 12-2 and 12-3 NM cables can get real crowded and you end up with an extra conductor or two. If it's new construction I like to use 4 steel boxes ganged together for the switch box. I feed 2 circuits to the switch box, one for the heater and one for the fan and lights. I then like to come out of the switch box and go up with 1/2" EMT to a 4x4x2-1/8" j-box on top of the plate. I then go the rest of the way(usually less than 3') with 1/2" flex to the fan/heater/light. I pull 2 #12 neutrals, one for the heater circuit and one for the fan & lights, one #12 ungrounded conductor for each function and a #12 green all THHN. This may seem like a lot of trouble but it makes for a more managable situation in the small wiring space the fan/heat/light provides and avoids extra conductors or re-identifying conductors like when using a combination of NM cables.

Fred,
Why not flex all the way?

Redsy, Our local inspector insists you can't use it in lengths exceeding 6'. I've argued this with him and it's just easier to do the EMT thing and keep the flex short. You can read him 350-10(a) until you're hoarse and he just doesn't get it.

Cieling heat, how efficent...is there some sort of rogain dependent market looking to kick the habit via folicle heat treatment?

Yeah, Inefficient and expensive... about $80 for the cheapest ones...


I use 14-3-G NMB Cable for vent and light and use a 12-2-G NMB Cable on a dedicated circuit for the heater. I recommend a timer/switch for the heater to reduce the chance of an outrageous electric bill.

The importnat thing, in my opinion, is to ignore any manufacturers instructions that have you running the grounded conductor for any load in a different cable from the the ungrounded conductor.

In interior windowless bath rooms I offer the owner a three way switch wired to turn on the night light or the main light depending on it's position. Iknow that a constantly lit night light does use some electricity but some home owners want that feature.
--
Tom

Tom,

That's the subject I was waiting to come up. I've seen these things wired a number of ways and most are not correct. I just saw an installation yesterday that pulled a neutral from some other location just to make it work. (3 wire and a 1 wire cable)


Virgil,

I was waiting to hear how you'd get so many #12s in there, because I've heard you say that's all you use. (you surprised me with the 14/3)

Bill

We aren't allowed to have such things. CA energy regs prohibit the use of the incandescent light in a bathroom. Does anybody know of a unit made with fluorescents?

Electure,

Are you serious?
Is this just the bathroom, or other rooms too?

Bill

Bill, you get the credit for the fact that I now use #14 for lighting loads...

Heck, someday I might even use #14 for convenience receptacles (but a 15A breaker makes them "less convenient" in my opinion, subject to callbacks when the circuit is "overloaded"...)

Tom, I like the SPDT switch idea (not really a 3-way in that usage) for the nite-lite.

I had a call back once where I had to install a stacked (duplex) switch at a $7 loss because the Owner didn't want the 7W bulb burning 24-7.

Wish I had thought of the SPDT thing then...

The last few I've installed didn't have the nite-lites...(?!?)

Yes, Bill, I'm serious.
Kitchens too. It's Sunday, but I'll try to find the Code reference and post it ASAP.

They still sell (& I'd presume install) them here. I have one with a fluor retrofit lamp in it. (please don't call the authorities on me).
I ran dedicated circuit to a metal switchbox, and used 12-4/g type M/C cable up to the unit.


[This message has been edited by electure (edited 10-21-2001).]

electure, Nutone makes a fan/fluorescent light combo. It complies with the Title 24 requirement of fluorescent lighting in bathrooms and kitchens here in CA.

Once again, my foot is in my mouth!!
I received an e-mail (good) from "Ross" with this CA Title 24 excerpt:
"Each room containing a shower or bathtub shall have at least one luminaire with lamp(s) with an efficacy of 40 lumens per watt or greater. If there is more than 1 luminaire in the room, the high efficacy luminaire shall be switched at an entrance to the room."

Ross's interpretation of this, (as well as mine), is that there must be @ least 1 fluorescent fixture in a bathroom, and doesn't prohibit the use of incandescent lights in addition to the fluorescent.
Kitchens are a different deal altogether.
Thanks, Ross.
(me & my big mouth)
Welcome to Bill in LA!
Bill, is this unit also available with a heater? (my Nutone catalog is a dinosaur)

[This message has been edited by electure (edited 10-23-2001).]

That makes more sense now. I couldn't see how Californian ladies could get their makup on straight with just a dinky fluorescent light over the vanity. (Unless the hype is all true and they don't need it? ) It's probably not a very flattering light to skin-tones either, is it?

Bill

To All:
I cant believe what I just read on a heat/vent/light/night light combo, at least in my area and in the code two cables run to this unit would be gigged immediately.
Via 300-3(b) all conductors of the same circcuit and where used, the neutral and all wquipment grounding conductors shall be contained with in the same raceway, cabletray,trench, cable or cord.,,,
12-4 or 12-5 MC works nicely on these units.

bordew,

I had read the same thing. That was part of my reason for asking the question. I've never seen them wired with one cable though.


Bill

Bordew,
If the heater is on a different circuit from the light&fan, why could you not run 2 cables?

Yeah, I thought the heater would *have* to be dedicated, considering its load (1500W)...

It is continuous, unless there's a timer, I suppose...(?)

I've got a dedicated 20amp circuit to mine, with a 15 min. spring-wound timer for the heater.
If a guy has 2 circuits to the unit, then there shouldn't be a problem with 2 cables, should there?
BTW, Nobody makes 12-5 MC cable that I know of. AFC makes "home run cable" that comes in 6 and 8 conductor configurations, but generally MC is available in 2, 3, or 4 conductor.

Here's what I was thinking about. There is only a limited space inside these things for wiring and separate cables would mean separate Neutrals would have to be run and really cram up the inside. If there was only one neutral to the unit then it would have to be inside the same cable or raceway with all the others. If the Neutrals in the unit for the 3 functions are tied together it can't be fed from more than 1 cable without being a violation. I don't know that the average person wiring these things would be aware of that.


I don't see why it couldn't be on 1 20A circuit with a 12/4+Gr MC feed to it though.

Bill


[This message has been edited by Bill Addiss (edited 10-24-2001).]

I'm not inclined to add 4-wire + G cables to the stock in my van, and I don't trust my remembering to bring a length on the day that I need it.

Given a 3-function unit (fan/heat/light), have the branch circuit homerun at the switch and use a 12/3 and a 12/2 seperating the neutrals in the unit j-box (the component loads present on pigtails each with their own neutrals). The j-box is tight, though, but not impossible.

Substitute a 12/3 for the 12/2 in a 4-function unit.

Let's say the 12/2 has the light, hot and neutral. That's one circuit and it satisfies 300-3(b). Same with the 12/3 on the heat/fan. The violation of 300-3(b) comes when I don't seperate the neutrals or choose to use only one.

Al

[This message has been edited by ElectricAL (edited 10-24-2001).]

Al,

I agree. As long as the neutrals are separated properly in the unit there shouldn't be any problem. That's not what I usually see though.

Bill

According to manufacturere specifications. Heat/vent/light the three unit or the 4-unit models are just that meant to be wired as a single unit. It sounds like some of us redefine the code as we go along.
As far as the extra neutral goes, it reminds me of the ' House Doctor ' Ron Hazelwood, he was showing how to wire a ceiling fan and to include two switches, so what does he do, he runs two 2/c, instead of a 3/c. and he dead ends the extra neutral.
My point is these units are just that units, and are meant to be wired as such. To physically seperate them for convenience doesnt make the job by 'Code'. At least not in my area.

As I have previously stated, none of us know everything. I am here to learn. I have been aware of the code requirement to keep conductors in close proximity for years(surprise, I even know why we need to). However, I am an industrial E & I mechanic, and not a residential wireman. Therefore, I simply have not had to install these fixtures, and don't know the ckt. requirements. I have, however, installed and programmed VFDs and other motor control circuitry, UPS systems, process control instrumentation, and intrinsically safe and explosion-proof equipment in hazardous locations. I prefer to ask questions and offer suggestions in an environment where I won't be talked down to.

bordew,

I'm not convinced that these units are made to be wired as such exclusively. The do come with separate sockets, each with their own set of tails (B & W), so there are no modifications being made inside. I don't recall how the instructions read, but the recomendations (single cable, raceway, etc.) made may be for the purpose of simplicity and a 'can't go wrong' solution. I don't believe that I've ever seen these installed with a single cable or raceway though.


Bill

Redsy
I wasnt talking down to YOU or anyone, this is how we teach apprentices, also not to take short-ccuts and to follow the code as much as possible because as you are well aware the code is bare minimum, it is not the ultimate source.
AS contractors if we dont do it to code who will

Bill:
This is probably true, however it is a single enclosure and the recomended way is to pipe it or use greenfield. As far as i can tell the plugs inside are to facilitate removal of a bad element. ie fan or heater etc.
It is recomended for a 20 amp circuit because of the heating element.
My point was that in MY area, here in Ohio and I believe that is what I said, we must adhere to 300-3(b).
I have done it this way in new construction and snaked it through walls in old construction.

bordew,

We all want to be code compliant. I understood what you said, but am not sure that 300-3(b) means that only 1 cable or raceway is permitted as a wiring method in this instance. As I look at it it seems to be talking about circuits in the sense of 'complete circuits'. I don't see why 3 switches connected to 3 individual receptacles could not be considered 3 circuits and be allowed in separate cables or raceways. In that sense, more than one cable would not be a violation.


Bill

Now that I'm thoroughly confused...

Where does it say I can't run two ciruits?
Is it because there's only one "nameplate"?
Clue me in here...

I *never* intend to bust code... When I do, it is simply out of sheer ignorance... My 99 NEC is very dogeared, so it isn't from a lack of trying...



OK, I have to admit I haven't read the instructions for those in years... Have they really changed that much? If memory serves me correctly, I recall that the instructions for the units I install reccomend the very procedure I use... Hixson was adamant about reading instructions, so I have read them at one time! Just not recently...

Bill,
As far as wire space, I haven't noticed the capacity labelled in these, stamped or otherwise... Does the UL sticker "exempt" them as per a motor "peckerhead"?

I've found there's ample room if you use the 3" outside the box, 6" minimum rule to the fullest...



[This message has been edited by sparky66wv (edited 10-25-2001).]

Bordew,
I've sent more than 1 e-mail to Ron Hazelton (the House Doctor), and to HGTV for his non-code, non safety conscious shows. Unfortunately, many DIY people watch these shows.
(I compare him to the other "Hazeldude", Joe Hazelwood, who got drunk and ran the Exxon Valdez up on a reef)

Bill,
Interesting point regarding the 3 switches. What about a split wired receptacle fed with 2 separate 2-conductor cables? Or, if you wanted to switch half a receptacle and ran out of 3-conductor cable, would it be a violation to run 2 separate 2-conductor cables?

I save instructions. I have before me a Nutone model 9427P, L,F,H. It shows a 3-function control with 2 separate 3-wires to the unit. There are 7 wirenuts shown in the unit's 'peckerhead' , or whatever it's called.

Note 3 ( out of 9) reads as follows;

Installatiuon work and electrical wiring must be done by a qualified person(s) in accordance with all applicable codes and standards, including fire-rated construction codes and standards

Sparky,
I know it's early in the morning, but..
If 2 separate 3-condoctor cables are shown, what do they show happening to the unused hot?

Redsy,

regarding your question:
As long as the neutral connecting tab on the receptacle was broken off and each cable had it's own neutral I don't see a problem with it. Do you?

Bill

Sparky,

I can't figure what the 7 wirenuts are. Unless they are including one to cap the unused wire? I'm getting 6 wirenuts and 1 unused wire. Are you sure it's not a 4 function? (w/nightlight)


Fan Hot
Light Hot
Both Neutrals

Heat Hot
Heat Neutral

Both Grounds

Bill,
I don't see any problem, either. That is why I brought it up.
As far as the extra wirenut in the drawing, I also wonder about the other hot.

[This message has been edited by Redsy (edited 10-27-2001).]

My question to Redsy, would be, why would you even run two, 2/c for a split receptacle ?
Second, 210-4(b), says that if this multi-wire goes to the same yoke there shall be a breaker tie, a 240 v circuit with a split recceptacle, and now there are two neutrals in parallel, which are smaller than no. 1/0.
Since it is a multi-wire circuit you would only need one neutral.

The neutrals aren't parallel because they have different loads? They would only be parallel if they were connected on both ends, right? (i.e. the tab "bridge" isn't removed)

I'm asking, not "telling" here...

Sparky66;
I would think that they would be regardless of the tab. First the circuit is a Edison 3-wire, one neutral. red and black going back to the panel to a 2-pole breaker or two single poles with a tie-lock, the tie-lock because they both go to the same strap or yoke.
By removing the tab, now you have 240 volts at the receptacles, since it is a duplex, with two seperate neutrals. Yeah you are right I dont think they would be parallel, but the problem if ther are two seperate breakers then that would create a problem of safty. and one breaker could be off misleading the electrician into thinking that the receptacle is dead when its still hot, thus the need for a 3/c with a tie-lock on the breaker and no split neutral. IMO thats asking for trouble.

(pokes head out of crawlspace to post..)

Bill, I'll scan / e-mail it to you ok?

(returns to add to cobbweb collection on hat...)

Let's say one runs a 3-conductor multiwire for the two small appliance loads in a kitchen. Obviously, after the neutral is split to each GFCI, it cannot be reconnected, or the GFCI's won't work properly. Let's say it is a small kitchen with limited counter space and either 2 gang with double duplex, or a split receptacle on a single gang is on the GFCI's load sides... Remembering the FPN that suggests alternating the circuits for better diversity, let's assume that each box will contain both circuits.

Would this be improper as well?
Let's assume there are handle-ties, or a double pole breaker.

What if I run two 2-Cond cables both from the same side of the panel? That is, there's zero volts between the hot conductors.

Then I'd have a common trip breaker and I'd have to have two neutrals.

Then, in Virgil's kitchen setup just above, there's no 240 V on the counter in the kitchen.

I'd have to balance the service a little differently, though.

Al

[This message has been edited by ElectricAL (edited 10-27-2001).]

[This message has been edited by ElectricAL (edited 10-27-2001).]

Bordew,
It is only a multi-wire ckt. if you run a single neutral from different hots. What if you start your circuits from the 2 different breakers fed from the same bus. Would it be a violation?

ElectricAL,
What you describe is not a multi-wire ckt.
Although it may be foolish to do so, you could install that configuration without handle ties. Correct?
BTW,
I think the reason handle-ties are not REQUIRED if wired as 2 separate ckts. is because the 2nd neutral in the box would tip-off someone that there is another circuit involved.

[This message has been edited by Redsy (edited 10-27-2001).]

Virgil;
as to your 10-25 post here;

As far as wire space, I haven't noticed the capacity labelled in these, stamped or otherwise... Does the UL sticker "exempt" them as per a motor "peckerhead"?

I see that 300-15 (b) apparently allows blowing off 314 ( fill, etc...)

some real interesting changes going on here.....

For what an outsider's 2-cents is worth, I can't see any problem with running a separate cable for the heater, so long as the heater neutral is kept separate from the other neutrals.

Wired in this way, I would regard the heater section as being a separate circuit (or "sub-circuit" if you will), but one which just happens to have its load in the same physical fitting as the lights & fan motor.

Wow!,

Are We going for the record here?
Sparky, true to his word, has sent me a scan of the instruction sheet for a Nutone unit. I guess that it's a good thing to keep these things. (too bad he didn't keep the ones in English!)

M****a!
(skulks off clutching his green card..) http://translation2.paralink.com/

[This message has been edited by sparky (edited 10-27-2001).]

[This message has been edited by Webmaster (edited 10-27-2001).]

Redsy,

I take your point. I haven't really appreciated the narrowness of the definition of "Branch Circuit, Multiwire". I had tried looking up Multiwire earlier and missed it. . .has to be voltage difference between the hot conductors to be multiwire.

Seems to me that two hots from the same bus should qualify, though. If I'm moving fast or in low light, I could easily overlook the missing tabs, I could mistake the hookup for a wire-through, using the device to splice the conductors.

Al

See Below

[This message has been edited by electure (edited 10-28-2001).]

Easy Translator from SoCA white guy:
Blanco=white, Negro=Black, Azul=Blue, Rojo=Red. Alambres=wires, Ventilador=Fan, Luz=Light, Calefaccion=Heat,thus Calentador=Heater. Linea de Entrada=Point of Entry, Controle de 3 funcciones=(Come on, anybody can figure that one out!)
Hey! the first time it didn't show up as posted! I didn't mean to do it twice!



[This message has been edited by electure (edited 10-28-2001).]

electure,
Thanks for the translation. I will now refer to myself as Rojo.

Rojo-sy?

Sr de gracias. Electure

Entonces otra vez el código es manipulado por el deseo de la comunidad de la fabricación aquí, como 300.15B parecería adaptado a este argumento(guión).

Uh, buenos nachos?

(Good Doritos)

El taco bell, y a burrito luncho, hotso salso. Burno le bungo.
Rojo-sy
si wolfo

Hee Hee! LOL

El majoro threadjacko!

Donde esta el gato?

No... It's not relevant at all but it's one of the few things I can ask in Spanish! Now if I could just redefine a key as an upside down question mark....

Por qué
El Gato es Muerto!


Bill (Guillermo)

[This message has been edited by Bill Addiss (edited 10-28-2001).]

Hey Rojo-sy, try some ice cream for that bungo thing you got there.
and Redsy ate 'el gato' in that burrito he had.

So,

Anyway, before we get too carried away ...
Why does this diagram show an unswitched hot going up into the unit and why does the white (Blanco) wire from the left cable need a small jumper on it above? (2 wirenuts with jumper in between) ??

Bill

It appears to be a constant feed Bill, i can only think of a nite-light as a 4th entity.

I can't imagine why the 2 wire nuts are in series.

They even show ( in another of the generic instructions variations) the heat lamps & vent operating together.

How stupido!

Sparky,

I was wondering about a nite-lite too, but wouldn't that be on a switch?

Bill

Sparky,

I went to Nutone and found that this model is a Fan/Heat-Bulb fixture. That wasn't what I was originally referring to, but the wiring is still a mystery.

hmmmm,
have they a tech that would like to comment?

Uno questionne stupido, perhaps, but what is the physical arrangement of all the various items in these combo units?

We have combined fans/lights in a few places here (useful for the 2 days of summer we get each year!), but I've never seen one with a heater incorporated as well.

Two-Bulb Heat-A-Vent

• Two-Bulb Heat-A-Vent-Type IC
• It's a radiant heater and a vent, too.
• Uses 2 BR40/R40 infrared heat lamps or one incandescent lamp and one heat lamp (not included)
• 70 CFM ventilation, 3.5 sones
• Automatic reset for thermal protection

(from this page )

I usually see the ones with the resistive heating element >> 9965

Bill

Redsy:
A multi-wire circuit is a 3-wire edison, the nice thing about it is if you balance the loads the neutral carries no current.
The picture is the same one I saw yesterday at HD on a heat/vent/light unit a 3 switch deal, I posted the about that discovery but it never showed up.
The Nu-tone i saw friday at my supplier recomended a seperate 20 amp ccircuit. This is in addition to the mandated 20 amp circcuit for the bathroom. This is how i do it too. As i implied before I believe that two cables is in violation, even if I didnt Our inspectors insist that we use flex or MC Depending on how many switches are involved.
Three (3) switches we can use 12-4 MC cable and 4 switches flex, greenfield. I usually make up 2 or 3 ahead of time cut to different lengths just to have them on hand.

Ah, thanks Bill.

For some reason I was thinking of big light/fan ceiling fixtures (i.e. those with exposed 36" diameter blades).

Not sure why I was going down that track - Evrything now suddenly makes sense!

Paul,

Just curious,
How did you envision Heat being an available option on one of those fans?

Bill

Thanks, Paul... I haven't laughed like that in weeks!

Yeah, I know, stupid foreigner!

I was envisaging some sort of circular heating element sandwiched between the central light(s) and the fan blades. I guess the "bathroom" bit should have given me a clue.... (Oh well, it's not been the best of weeks!)
*
[Pause while foot is extracted from mouth.]
*
I think I was being influenced by some ceiling fixtures here which have a center light around which is a circular heating element backed by a reflector. They're not very common these days, but they're often found as add-ons in very old unmodernized properties which have their main "facility" at the back door and otherwise unheated. Heating element was almost always 750W.

Bill:
To see what I mean, see TLC catalog pg. 116, item code TL GHL750.

Gee,
I thought I had supplied a way to connect these things, but all the Romex-Men don't want to carry 15' of M/C on their truck. I'm Mad, and they're lazy.

ZZZZZZZZ. . .Huh?. . .Wha. . .oh, it's not quitin' time yet. . . lemme sleep. . .ZZZZZZZZZZZZZ

bordew,
Do you know the origin of the edison term? Also, is a 4-wire multiwire ckt. called edison?
BTW,
Another advantage to on multi-wire ckts. is less voltage drop. And, more significantly, less conduit fill on raceway jobs.

Rojo-sy,

I think you'll find the "Edison" term for 3-wire comes from the early DC systems installed by the Edison Co. Grounded neutral conductor, one positive hot and one negative hot. Not sure about over there, but in the old 3-w DC systems here each hot line was called an "outer."

Redsy:
the term Edison 3-wire i learned about 35 years ago when I was an apprentice and it has stuck ever since.
It came originally from not sure, but in one of our appren text books was a piccture of a xfmr secondary with a center tap ergo edison 3-wire and was the term used by the instructor and it fit.
But Edison himself was a big fan of DC and his major competitor George Westinghouse was an AC proponent. Big debate bout the turn of the century, and it came down to an Execution of some murderer in NY as to use AC or DC for the kill, and it turned out they used AC and from what I remember it was decided to use AC.
I have heard 3-phase wye being called an edison but the definition just doesnt fit. Appropriately probably should be called a Westinghouse 3-wire.

Paul,
I think you have nailed it!
Most likely the term was developed from purchased power from the Edison Company which used DC systems, and before the Niagra Dam AC power Plant project by Tesla and Westinghouse proved AC's benefits - leading to the exclusive use of AC power systems.

As mentioned, Thomas Edison was reluctant to accept the use of AC, and promoted the use of DC. This probably was from envy and jealousness of Tesla's acceptance by Edison's rival, George Westinghouse!
Also, while Tesla worked for Edison Labs, he described the same thing about using AC instead of DC for system power, as he did to his Electrical Engineering Professor in College.
As what resulted from the MSEE Professor, Edison reacted the same way!
" Are You Crazy!!??, AC CAN NOT BE USED FOR ANYTHING PRACTACLE!!!"
[gee, I wonder if they were right? ]

Ok, enough with the Ancient History report

The term "Edison Circuit" may have been in some reference to circuits connected to Electro-Chemical cells.

The "Edison-Lelande" cell was a commonly used "Wet" cell, modeled from the famous "Leclanche Cell" experimental models.

The circuits made up in Edison Labs would have certainly included 3 wire DC circuits, made up by using two Edison Cells in Series, with a "Center Tap" between the two cells.
It's just a guess of mine that the term may have originated from this, but became familiar to the Edison Power Company's commonly used multiwire DC circuits.

FYI, and for more trivia , the 3 wire DC system can be derived from the following setups:

<OL TYPE=1>

[*] From two Cells connected in Series, "Center Tap" made between the Cells,

[*] From two Batteries connected in Series, "Center Tap" made between the Batteries,

[*] From One "3-wire" DC Generator, which has a "Center Tap" between two Field Coils,

[*] From two individual 2-wire DC Generators connected in Series, and a "Center Tap" made between the two Generators,

[*] From a "Combination" of a 2-wire DC Generator connected in Parallel with two Batteries or Cells, which are connected in Series with each other - and deriving the "Neutral" [proper term here!] from a "Center Tap" between the two Batteries or Cells.
</OL>

If these seem nearly impossible to invision, posted schematics can help unmask these obsolete systems.
I use the term "Obsolete" as to the extensive use of DC for consumer power systems [how the consumer buys Kilowatt Hours].
3-wire DC power supplies are far from being obsolete!
DC Power supplies for the PC you are using right now, have a 3-wire output.

Sorry to throw this DC stuff into a thread about Heater/Fan/Light combo's!
Just felt the urge again

Nurse Diesel Is Coming To Get Me!

Scott SET

Scott
Is that Nurse Diesel or Ratchet?

First 3-Pager I've seen! Yes?

Who's Nurse Diesel?


Bill

From some of my reading, the fight between Edison & Westinghouse reached some pretty bizarre proportions at one point. Apparently Edison once claimed that AC of almost any level was extremely dangerous but that DC of up to several hundred volts (700V if I recall correctly) was quite harmless!

A challenge even went out for two men to be given shocks in 100V increments, one AC the other DC, until one cried "Enough!" The challenge was wisely refused.

It seems that it was largely due to Edison's influence that NY adopted AC for the first electric chair in 1890, although Westinghouse refused to sell them a generator.

Ignoring the fact that in certain areas one had little choice over the power available, Edison made much of th fact that Westinghouse lit his own home with DC.

Despite being a genius in many ways, this seems to be one time that Edison really got it wrong. I wonder if his thought processes would have been different if he had not had so muchat stake finacially.

By the way, some old 3-W DC distribution (at 200/400 to 250/500V) was in use here until the 1960s.

[With apologies to Bill for continuing the topic detour.]

Paul,

I think that we've covered the original topic adequately. This is all interesting stuff. I've been meaning to start a 'History' section here but haven't had the time.

Maybe soon...

Bill

I'm sure many people would find discussions of historical aspects quite fascinating - I certainly do. There's a lot of electrical history which explains why things are done a certain way today.

May i second the vote on ' electrical history'

send me back to school..this time i'll behave!

Oh, Nurse Diesel was on High Anxiety. Her and Harvey Korman were into odd role playing and bondage.
She was a real agro -, aaahhh, let's just say the word rhymes with Ditch

The two of them kept administering high doses of meds and torture to patients - hence the "Oh No! Here Comes Nurse Diesel" term

Ya, I know - it's lame It's another one of those "Inside Sayings".
Most people have never seen High Anxiety, or like the movie. It's not on the top 10 for me [like the all-time classic Blazing Saddles], but it's within the top 150.

Man, she was bu** ugly!!! (need a smilee for "Yuck and Yikes" together)

Scott SET

Oh yes... classic Mel Brooks!

(I didn't remember her name, though)

[shudder]