Convert 110V DC Wiring to 22O AC

[michiganhotrod1]

Hi all;
I have a 1940's commercial building in Detroit that was used most recently as a print shop; now it is my toy-box. It has 110 Volt Direct Current lines running all over, that were used to power the printing presses.
There is no 220 AC outlet in the building (which is three phase, BTW). I need 220 for my compressor, and a Millermatic 250 wire feed welder.
Would it be practical, and safe to reconfigure these 110 DC circuits at the main panel to run 220 AC, and change out the outlets for this? The wire looks pretty thick, though I cannot tell what gauge it is.
Any problems you can see in doing this? I will of course need to remove the Ther rectifier from the system; I think it is disconnected anyway now. I need to get a professional to convert the circuits (I am OK on doing 110 wiring, but don't know enough about this to attempt it ), but there are so many crooks and idiots in this area I would like to be educated before I get someone to do this.
Thanks,
Mark

 

[SGKent]

Hi all;
I have a 1940's commercial building in Detroit that was used most recently as a print shop; now it is my toy-box. It has 110 Volt Direct Current lines running all over, that were used to power the printing presses.
There is no 220 AC outlet in the building (which is three phase, BTW). I need 220 for my compressor, and a Millermatic 250 wire feed welder.
Would it be practical, and safe to reconfigure these 110 DC circuits at the main panel to run 220 AC, and change out the outlets for this? The wire looks pretty thick, though I cannot tell what gauge it is.
Any problems you can see in doing this? I will of course need to remove the Ther rectifier from the system; I think it is disconnected anyway now. I need to get a professional to convert the circuits (I am OK on doing 110 wiring, but don't know enough about this to attempt it ), but there are so many crooks and idiots in this area I would like to be educated before I get someone to do this.
Thanks,
Mark

Are you sure that building isn't 110 AC?

 

[nehog]

Without an inspection no one can answer your question... Likely any good electrical contractor won't try to re-use the existing wiring as it won't meet code. You'll probably be cheaper off running new wires as needed.

 

[ForceFed70]

If it's truely 110DC be very careful. DC is much more dangerous than AC and 110VDC could easily kill you.

 

[Thruxton]

I know this is an absolutely useless post which I try usually (and often unsuccessfully) not to make, but this is really fascinating, and I can't wait for the old pro's to chime in on this!

 

[Alchymist]

If it's truely 110DC be very careful. DC is much more dangerous than AC and 110VDC could easily kill you.

While 110 VDC will kill, it is no more dangerous than 120 VAC. Actually, AC is 120 volts RMS, and the peak voltage is 170 volts! Same safety rules apply to both.

 

[Gooch]

While 110 VDC will kill, it is no more dangerous than 120 VAC. Actually, AC is 120 volts RMS, and the peak voltage is 170 volts! Same safety rules apply to both.

120VAC is the most commonly associated voltage with electrocutions.

 

[Gregishome]

Hi all;
I have a 1940's commercial building in Detroit that was used most recently as a print shop; now it is my toy-box. It has 110 Volt Direct Current lines running all over, that were used to power the printing presses.
There is no 220 AC outlet in the building (which is three phase, BTW). I need 220 for my compressor, and a Millermatic 250 wire feed welder.
Would it be practical, and safe to reconfigure these 110 DC circuits at the main panel to run 220 AC, and change out the outlets for this? The wire looks pretty thick, though I cannot tell what gauge it is.
Any problems you can see in doing this? I will of course need to remove the Ther rectifier from the system; I think it is disconnected anyway now. I need to get a professional to convert the circuits (I am OK on doing 110 wiring, but don't know enough about this to attempt it ), but there are so many crooks and idiots in this area I would like to be educated before I get someone to do this.
Thanks,
Mark

Wow, you must live in Washington D.C. area

 

[michiganhotrod1]

It is 110 DC; all of the boxes are labeled so, and have unique outlet configurations. They were supplied by this giant rectifier, that has been removed from the circuit. The prior owner said the system was made for more efficient motors on the printing presses.
Unfortunately, what I seem to get are the knucklehead electricians who say "duh, never seen that before". I was hoping to get a little more information so I can more than guess at this.
M

 

[Boiler]

120VAC is the most commonly associated voltage with electrocutions.

It is also thousands of times more common. It doesn't prove it's more dangerous.

 

[justsam]

I know this is an absolutely useless post which I try usually (and often unsuccessfully) not to make, but this is really fascinating, and I can't wait for the old pro's to chime in on this!

I am not a pro, but I am old, so half credit.

To the OP what was the input to the rectifier? Was it single phase AC at 120VAC, 60 HZ, or was there some oher conversion ahead of the rectifier?

I agree with nehog, that I do not believe a contractor will touch it with the old wire, regardless of gauge.

How many conductors are at the outlets, just two or three? Again at a minimum, new code wll require hot, neutral and ground.

Is there a transformer of any sort on the site?

 

[Terry454]

In the late 1960s I started my career with an electric utility making DC for the Edison System -- 120/240 volts direct current. That System went away in the early 1970s, so you are not likely to find electricians still working who are familiar with that equipment.

As painful as it may be you are going to have to start from scratch and put in a up to date AC system. As others have cited no one is going to use that old wire without knowing its integrity, and you shouldn't risk your building and its contents by trying to do that. Retire all that DC equipment in place as the historical artifacts they are, and move on safely.
Terry

 

[Gary S]

I agree with nehog, that I do not believe a contractor will touch it with the old wire, regardless of gauge.

Totally agree. No self respecting electrician would risk his license reusing the existing wiring if it doesn't meet today's code. Call a licensed electrician and have him tell you what you have, what can be done with it, and what needs to be done with it.

 

[rockwithjason]

we would need much more information to make an informed comment on it. is there any rating information printed on the wire? this will tell you most of what you need to know. the wire size, temperature rating, voltage rating and gauge all play a factor. if the wire is up to snuff on the ratings and the gauge size is workable then you have a shot at reusing it. if not then i suggest hiring some knuckle heads and tearing it all out for salvage then using the money for a rewire job.

 

[casetractorfarmer]

I think we need some photo to get a better idea of what you have

 

[Kevin C]

"Edison carried out a campaign to discourage the use[18] of alternating current, including spreading disinformation on fatal AC accidents, publicly killing animals, and lobbying against the use of AC in state legislatures. Edison directed his technicians, primarily Arthur Kennelly and Harold P. Brown,[19] to preside over several AC-driven killings of animals, primarily stray cats and dogs but also unwanted cattle and horses. [20] Acting on these directives, they were to demonstrate to the press that alternating current was more dangerous than Edison's system of direct current.[21]"

http://en.wikipedia.org/wiki/War_of_Currents

"By 2006, there were only 60 customers using DC service, and on November 14, 2007, the last direct-current distribution by Con Edison was shut down. Customers still using DC were provided with on-site AC to DC rectifiers.[33]"

Nothing to offer, but the post did get me to read about the history of supplying DC power in the US. I had no idea that it was in use within the last five years.

Kevin

 

[ddawg16]

Love reading about the history of it....Edison...while brilliant....was also a jerk....When Telsa proved that AC was better....Edison just coudn't go along with it...

Anyway...getting back on topic....part of me says "Yea, you have to be carefull with that old wiring....but...if it's good....i.e., insulation is solid....AC/DC.....all good....

What I think you really need to do is find out when the wireing was done....if it's over a 100 years old....time to replace...

 

[SGKent]

Ok - it was 110 DC and you got it by having a giant rectifier - probably an old selinium one. Wow. The wire will be a + and - only with no ground. The equipment was probably presses and lightbulbs as nothing else would work - you'd fry anything with a transformer in the power supply or require special DC to AC inverters to have AC again. Hate to say it but IMHO all the wiring, panels etc will need to come out. I am not an electirican but I have worked around electronics most of my life and I am 60 now. In all those years the only things I have ever seen on DC are indivdual items that ran off custom power supplies. I was aware that Edison lost out to Tesla over AC vs DC but was totally unaware that some DC power was still supplied in certain cities 50 - 75 years after Edison lost to Tesla's design. Today we are like 100+ years since Tesla won that argument. Wow. At least the copper will have some value when it gets torn out.

 

[theoldwizard1]

Hi all;
I have a 1940's commercial building in Detroit that was used most recently as a print shop; now it is my toy-box. It has 110 Volt Direct Current lines running all over, that were used to power the printing presses. There is no 220 AC outlet in the building (which is three phase, BTW).

Likely 208V 3 phase.

Many 220V items can be run on 208V directly or by changing a jumper inside.

Worse case, you can buy a transformer that will convert 1 leg to 220V

Old wiring = old insulation which is likely to fail sooner instead of later.

Pull the old wire out. Take it to a scrap yard and sell it.

 

[Alchymist]

Actually, there is still one DC voltage system still in use in the country - not high power, but it's distributed all over the country. Hint - its -48 VDC.

 

[nehog]

Ok - it was 110 DC and you got it by having a giant rectifier - probably an old selinium one...

Actually my money is on a mercury-vapor rectifier tube. These were common, and able to handle the power needed. They were very impressive as well, usually wired as a full-wave bridge.

I used to use these when working in a movie theater, they were used to power the big projection arc lamps (which require DC). Typically the tubes would last a year or more in theater use, so they were reliable. And they were trivial to replace (unclip the anode connector, and unscrew like a light bulb!)

 

[Thruxton]

Telephone system?

 

[Mazdaratti3]

Telephone system?

My guess also.

 

[Norcal]

Telephone system?

Yup.

 

[Mmfh]

I thought the telephone system used 24v dc

 

[Alchymist]

I thought the telephone system used 24v dc

http://en.wikipedia.org/wiki/Tip_and_ring

 

[Kevin C]

Actually, there is still one DC voltage system still in use in the country - not high power, but it's distributed all over the country. Hint - its -48 VDC.

Who knew? Until this thread started I had no idea this was done.

"When electrical energy is required to be transmitted over very long distances, it is more economical to transmit using direct current instead of alternating current. For a long transmission line, the lower losses and reduced construction cost of a DC line can offset the additional cost of converter stations at each end. Also, at high AC voltages, significant (although economically acceptable) amounts of energy are lost due to corona discharge, the capacitance between phases or, in the case of buried cables, between phases and the soil or water in which the cable is buried.

HVDC is also used for long submarine cables because over about 30 km length AC can no longer be applied. In that case special high voltage cables for DC are built. Many submarine cable connections – up to 600 km length – are in use nowadays."

http://en.wikipedia.org/wiki/Electric_power_transmission


"The Pacific DC Intertie (also called Path 65) is an electric power transmission line that transmits electricity from the Pacific Northwest to the Los Angeles area using high voltage direct current (HVDC). The line capacity is 3,100 megawatts, which is enough to serve two to three million Los Angeles households and is 48.7% of the Los Angeles Department of Water and Power (LADWP) electrical system's peak capacity.[1]"

http://en.wikipedia.org/wiki/Pacific_DC_Intertie



Kevin

 

[justsam]

I used to use these when working in a movie theater, they were used to power the big projection arc lamps (which require DC). Typically the tubes would last a year or more in theater use, so they were reliable. And they were trivial to replace (unclip the anode connector, and unscrew like a light bulb!)

Wow! You had the modern ones! I worked at a drive-in theater in Northern California and we had large motor/generator sets to power the arc projectors. Of course there were two of everything to make a "seamless" reel change.

When all was well I doubled up in the snack bar, and then did clean up when daylight. That was always interesting, but usually found some cash on the ground, among other "things".

To the OP
Thanks for making us all review a little history, and I believe the consensus is pull out what you can for salvage value, and start over.

 

[rlitman]

While 110 VDC will kill, it is no more dangerous than 120 VAC. Actually, AC is 120 volts RMS, and the peak voltage is 170 volts! Same safety rules apply to both.

This is misinformation.
The peak voltage is not as important as the RMS, as the RMS voltage gives you an idea of the power potential. A sinewave spends just as much time at the peak voltage, as it does at ZERO volts anyway.

Having been shocked by both 120V AC and 120V DC, I can personally confirm that your muscles react differently to a DC shock, and it is harder to release yourself from contact with the DC source in this situation.

Additionally, the potential for a hazardous arc flash from a 120V AC source is low (even at very high potential currents). Typically, arc flash hazards start at 480V on an AC system. The potential for a hazardous arc flash exists on 48VDC systems, and is very real on a 110V DC system. If you look closely, the maximum interrupt current rating for a breaker will be considerably lower for the same voltage in DC, than it will be for AC, which is why we have many more fuses than breakers in the 540V DC equipment we have at my work.

 

[Alchymist]

This is misinformation.
The peak voltage is not as important as the RMS, as the RMS voltage gives you an idea of the power potential. A sinewave spends just as much time at the peak voltage, as it does at ZERO volts anyway.

Having been shocked by both 120V AC and 120V DC, I can personally confirm that your muscles react differently to a DC shock, and it is harder to release yourself from contact with the DC source in this situation.

Additionally, the potential for a hazardous arc flash from a 120V AC source is low (even at very high potential currents). Typically, arc flash hazards start at 480V on an AC system. The potential for a hazardous arc flash exists on 48VDC systems, and is very real on a 110V DC system. If you look closely, the maximum interrupt current rating for a breaker will be considerably lower for the same voltage in DC, than it will be for AC, which is why we have many more fuses than breakers in the 540V DC equipment we have at my work.

Which part of "Same safety rules apply to both." did you miss? The intent of the comment was either way can kill you. How dead do you have to be to be dead? Depending on insulation values and contact resistance, the 170 v peak can cause current to flow where 110v DC might not, or at least to a lesser degree. Bottom line, don't touch either.

 

[MBfreak]

Hi guys.

Replace the old stuff. Old DC plants have a way of corroding and collecting dust particles due to the stationary electrical field.

As to the medical/safety aspects of AC at power frequencies compared to DC here is my $0,02´s worth.
European safety legislation specifies "Low Voltage Installations " to be below 1000 V RMS at 50 Hz or below 1500 VDC.( Pretty close to the sqrt2 factor)
The electrical safety courses I have been to over the years, required by legislation to keep my safety diploma intact, have always covered the actual impact on the human body from current passing thru.
And the medical doctors managing that part of the course use about the same electropathology stuff now as 40 years ago.
In that, the severity of an AC current at 50 Hz going thru the chest cavity at 10 mA is deemed as having the same risk as a DC current of 30 mA.
And no, I do not want to know how they found out.
Sorry, can not include the material since it is copyrighted. But a google on "electropathology " may be useful ( I have not tried)

Best regards

Ola

 

[Mmfh]

http://en.wikipedia.org/wiki/Tip_and_ring

Looks like I've been wrong about that for many years, Thanks.

 

[justsam]

Looks like I've been wrong about that for many years, Thanks.

Actually it depends on which end of the local loop you are on!

If you are talking about CPE (Customer Premise Equipment), or also called station equipment, you are right on, it is indeed -24VDC.

If you are talking about being in the CO (Central Office), it is -48VDC.

And to add a bit more to it, the ringing potential is a nominal 105 volts, at 20 Hz.

 

[nehog]

This is about the best writeup that I can find, and is accurate (IMHO!)

http://www.allaboutcircuits.com/vol_1/chpt_3/2.html

Each has factors that in the end seem to make it a toss-up as to which is safer.

 

[Brendanf]

Which part of "Same safety rules apply to both." did you miss? The intent of the comment was either way can kill you. How dead do you have to be to be dead? Depending on insulation values and contact resistance, the 170 v peak can cause current to flow where 110v DC might not, or at least to a lesser degree. Bottom line, don't touch either.

Your comments are ridiculous. DC is so much worse then AC for shock and damage to a human body. Just because the voltage is 60v less means absolutely nothing.

Getting back to the original thread here the best advice would be to gut the DC stuff from the building and start from scratch. Your going to need a licenced contractor to do the work aswell. You will also need to know what your incoming service is 3phase4wire or 3phase3wire and what voltage.

 

[Alchymist]

Your comments are ridiculous. DC is so much worse then AC for shock and damage to a human body. Just because the voltage is 60v less means absolutely nothing.

Getting back to the original thread here the best advice would be to gut the DC stuff from the building and start from scratch. Your going to need a licenced contractor to do the work aswell. You will also need to know what your incoming service is 3phase4wire or 3phase3wire and what voltage.

I suppose you are another one who has experienced both? So 60 volts difference is nothing? I suggest you re-read posts 31 and 34. 60 volts by itself, either AC or DC can kill under the right circumstances.

 

[Kevin C]

I know I'm new here... But I just want to mention that we are getting pretty off topic (I'm partly to blame as well) and this is kind of turning into a ........ contest.

To settle it, I will head out to my shop and compare shocks from AC and DC sources. I will post as to what one hurts more and if it was lethal.

 

[Brendanf]

I suppose you are another one who has experienced both? So 60 volts difference is nothing? I suggest you re-read posts 31 and 34. 60 volts by itself, either AC or DC can kill under the right circumstances.

Never had the misfortune of touching live DC. But I don't have to. I am a licensed electrician so I know through trainning and experience that you don't know what your talking about.

 

[Alchymist]

Never had the misfortune of touching live DC. But I don't have to. I am a licensed electrician so I know through trainning and experience that you don't know what your talking about.

And I know through experience that you're trolling ...if you were as trained and experienced as you claimed you would know that current in a shock situation depends on the path resistance, AND voltage level. Pretty simple concept - the higher the voltage for a given resistance, the higher the current.

And calling the idea of respecting the safety rules for both AC and DC ridiculous is itself ridiculous.... "nuff said.

 

[wellpoison]

Brendanf, please explain to me why NFPA 70E states that circuits 50V AC or less can be worked on energized, but circuits 100V DC or less can be worked on energized?

BTTT if the rectifier is removed then there is no way to supply DC power anyway. like prevously mentioned there probably was no ground wire run with the hot/neutral. your looking at a complete rewire.