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Multiple circuits through one conduit

pm's picture

There are several pieces of conduit coming out of my service panel that each have wires for more than one circuit running through them. Is that allowable?


It seems like it would be dangerous for someone working on the electrical not to know how many different circuits are running through a box when they open it up. On the other hand, running each circuit through it's own conduit means a conduit farm on the basement ceiling.

(post #100082, reply #1 of 36)

yep it is allowed, I do it all the time......

and yes it would be dangerous, and pretty hard on any appliances that are on those circuits, if someone just starts cutting SOME of those wires

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(post #100082, reply #2 of 36)

...most areas allow larger runs in the basement and into heavy use areas, which will have several circuits, and those may used to feed branches throughout the house..so whomever is working on the elec needs to be positive that the correct circuits are off...open the wrong Neutral and you will have real problems

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(post #100082, reply #3 of 36)

Multiple circuits through 1 conduit is the norm for any commercial installation. It's not usual in home installations, but may be found occasionally.


However; and I can't emphasize this enough!!!


DO NOT TOUCH THIS YOURSELF!!!
GET A LICENSED, PROFESSIONAL TO DO ANY WORK ON THIS!!!


They will probably have to trace the circuits, or take a number of precautions while working on this stuff, that the regular DIY'er would not think of; just to keep from blowing up the appliances, etc.


 


locolobo


Edmonton, Alberta, Canada


 

(post #100082, reply #5 of 36)

.DO NOT TOUCH THIS YOURSELF!!!
GET A LICENSED, PROFESSIONAL TO DO ANY WORK ON THIS!!!

.........that is more very good advice

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(post #100082, reply #6 of 36)

im as DIY as they come and have lots of conduit in own house with multiple circuits, loop feeders to outbuildings even, etc.  All labeled.  Am I or family in danger 'cause not a liscensed electrician?? - don't think so, inspector was a little surprised to see so much conduit in a house though, but no problems.  g


I kinda get turned off by these self serving 'licensed electrician' comments, unless the questioner really shows a total lack of any type of capability to understand. Sounds like HVAC-talk comments. . Some good, some bad, like any profession.


 


Son bought an $800,000 house that had all electrical installed by licensed union electricians, hardly anything labeled, cant even tell which breaker goes to what part of the house (at least there is a 42 breaker panel). whoopede do.


 

(post #100082, reply #7 of 36)

   

...." I kinda get turned off by these self serving 'licensed electrician' comments...."

junkhound , maybe you don't need a license to do your own elec,

some states don't require it, mine don't ,

so "can" the self-serving comments

also, I'm certain the poster did not work in missle silos either.......neither did I

he .... as a non- lincensed electrician.......questioned what he has in his house and it is being answered...or was.!

I'm a union Electrician, and the I have never marked pipes or j-boxes in a house, I don't care what it cost........!!!

the prints for the $800,000.00 house didn't include a panel schedule ?

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(post #100082, reply #8 of 36)

Then I would consider you to be an "exception", but I wouldn't get too [JOBSITE WORD]y if I were you. You may just be extremely lucky!!


Most DIY'rs have absolutely no clue as to how electricity can maim and kill. They have *maybe* gotten a minor shock in the past, and therfore consider themselves to be "immune" to electricity.  I have news for them... even licensed electricians get killed, mostly due to lack of respect for what can happen.


I worked on a mall addition in Abbotsford, BC; and in the old electrical room, there are a set of footprints on the floor and some metal splashes on the wall behind. This was all they could find of an electrician who accidently dropped a screwdriver in the high-voltage section of the main service.


Many years ago, my BIL spent 6 weeks in the hospital, and a year doing physio because he got careless with a light socket. He used to kid me about my turning off the breakers all the time. He doesn't do that anymore!


It doesn't take much to kill... in fact, most times it takes less power to kill a person than it takes to light a 40W bulb.


Electricity is an invisible killer. If you have a plumbing problem, you will usually see a leak, Carpenters can see the end results of their work. But electricians have to rely on meters, testers, Meggers, etc. and God help us if the batteries went dead without us noticing. Experience also has a lot to do with staying alive in this industry.


I get really tired of builders saying; Why don't you work "live"? My other electricians do!". I am an "old" electrician... and I plan to get "older", by not working stupid!


 


locolobo


Edmonton, Alberta, Canada

(post #100082, reply #9 of 36)

set of footprints on the floor and some metal splashes on the wall behind. This was all they could find of an electrician who accidently dropped a screwdriver in the high-voltage section of the main service.


Would very much like to see the official report on the event described, can you supply any references or new reports to that instance?   Thanks.

(post #100082, reply #11 of 36)

>>>

set of footprints on the floor and some metal splashes on the wall behind. This was all they could find of an electrician who accidently dropped a screwdriver in the high-voltage section of the main service.


Would very much like to see the official report on the event described, can you supply any references or new reports to that instance?   Thanks.


>>>


Yes, I would like that too, that's one colorful description.  Wish I was around to see the fireworks. Sounds like the guy was totally vaporized.  A la "Repo Man".


If no report handy, can you help shed some light on the situation please with these details?


1) High voltage: must be talking mega-Volts here?


2) metal splashes: From the screwdriver, or the tin-man sparky?


3) Are you sure the guy wasn't maxed out on his credit card bills and used the occasion to disappear?


Thanks again.


<G>


 

(post #100082, reply #12 of 36)

It must have happened 40 or 50 years ago when the original mall was built.


I came in when they were building a large addition to this mall; approx 1985... new main electrical room tying back to feed the old one.


Old mains were 15KV running about 600A


It was claimed that the metal splashes was what was left of his tool pouch.


I definitely saw the footprints... rubber melted right into the concrete. A bit hard to do if it was a put-up job.


 


locolobo


Edmonton, Alberta, Canada

(post #100082, reply #22 of 36)

Sure, everybody has a 15kv sub station in their house....
Bud

(post #100082, reply #35 of 36)

Read the next paragraph.


How many 40W, 60W, 100W bulbs do you have in a house??


Code tries to make it as safe for the homeowner as possible, but there is no way you can plan to stop ALL stupidity!!


You want to change a few fixtures... fine... TURN THE POWER OFF!!!


You want to work in your main panel... TURN THE MAIN BREAKER OFF!!! And then when you're finished, stand to the side when you turn it back on. All it takes is a little clipping of copper across the busses and you have a big "flash" coming at you, and they are PAINFULL !!!! I speak from personal experience on this one.


 


locolobo


Edmonton, Alberta, Canada

(post #100082, reply #18 of 36)

the voltage here is 4.16KV ....
there were 12 arcing faults...you can see one here !

BTW, I took these shots !

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(post #100082, reply #24 of 36)

Nice shots. Thanks for posting them.

They demonstrate some of the danger and why the enclosures are built like tanks. Arc blast and magnetic forces climb with voltage and short circuit current.

(post #100082, reply #25 of 36)

...." Nice shots..." you shoulda been there, I was literally frozen in place while it happened about 20' away.

The reason I posted them was to try to convey some idea of what <5KV was capable of during a fault, since there is some skepticism of the energy released at 15KV......

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(post #100082, reply #28 of 36)

"Electricity is an invisible killer. If you have a plumbing problem, you will usually see a leak, Carpenters can see the end results of their work. But electricians have to rely on meters, testers, Meggers, etc. and God help us if the batteries went dead without us noticing. Experience also has a lot to do with staying alive in this industry."

Not sure what is meant by the comment "carpenters can see the end results of their work", but I would disagree if you mean that DIY carpentry carries no risk of unseen dangers, like electical work.

How many back or eye injuries, circular saw, table saw, nail gun, etc. injuries occur every year by DIY carpenters untrained or unskilled in the carpentry trade, or in the use of dangerous tools? How many times is structural failure traceable to faulty framing details? While seldom as dramatic or as deadly as electrical errors, all trades need to be respected for their professionalism, and DIY in any trade carries its risks.

(post #100082, reply #29 of 36)

Since I am qualified in both trades, I will put it this way....


As a carpenter, if I mess up on building a fireplace mantel, I can see the problem; my customer can see the problem; a one-eyed pirate can see the problem! I KNOW how to fix it.


As an electrician, if I have a problem, I have to get out the meters and testers in order to trace the wiring to find the problem... all the while, the electricity is "ON". And then, is it a problem with MY wiring or is there a factory defect in the appliance which is causing the problem? Is there a leakage somewhere which is causing the breaker to trip? Shorts are easy to find... it's the gremlins in the wires which cause us to tear out our hair. Read some of the threads on GFCI breakers sometime.


If I blow a cut on the fireplace, I'm out a piece of wood


If I make a wrong guess as to whats wrong with the wiring, or if I can't find that particular gremlin, I may lose my life.


I'm not saying carpentry does not have hazards... every trade has hazards. It's just that electrical hazards are more likely to cause loss of life rather than loss of a digit. Many people carry on after losing a finger or two. It's hard to carry on when you just fried your heart muscle or your brain.


 


locolobo


Edmonton, Alberta, Canada.


 

(post #100082, reply #30 of 36)

If you have multi ciruits in the conduit  then you should have differant color wires for each hot .  If not get too the elecrical supply and get the colors that the bigbox don't have and fixit.

(post #100082, reply #31 of 36)

I think if his wires are already in I would trace and tape mark them.

For those who have fought for it Freedom has a flavor the protected will never know.

(post #100082, reply #32 of 36)

That would be simpler . But he would have more fun pulling new wire.

(post #100082, reply #33 of 36)

Sadist!

For those who have fought for it Freedom has a flavor the protected will never know.

(post #100082, reply #34 of 36)

Now if we could just get all the sadists and masochists to pair off...

Of course we all know how it progresses.

Masochists: 'Beat me. Beat me.'
Sadists : 'No, no.'

In the end none get what they really want. And it is all the sweeter because they don't.

(post #100082, reply #13 of 36)

Re: "hardly anything labeled, cant even tell which breaker goes to what part of the house (at least there is a 42 breaker panel). whoopede do."

I'm surprised you think this is a major problem. The panel schedule is usually the very last thing I worry about. I commonly put a couple of helpers on documenting the panel schedule on a clipboard while I fill out the time sheets and job documentation.

One runs around with a push in circuit tester and Wiggy while a second works the breakers. On a large structure they use a radio set. Forty circuits can be tracked in about ten minutes.

Their documentation goes to the shop where the secretary types it up on a standard panel schedule and label set. Even then the schedule is only broadly descriptive. Typically: 'Receptacles MBR. Lights MBR hall and front BR. Office comp cir W wall.' etcetera.

I once worked for a contractor that would spend dozens of man-hours writing descriptors on the sides of cables and sliding silly pieces of cable jacket onto the wires going to breakers. They would write the circuit number on every cover plate and the circuit arrangement was all grouped by area so the branch circuits were ordered N to S or similar. The owner was very proud of this system.

I got hired to cover a large house. First time I caught a helper fiddling with pieces of cable jacket and a sharpie I got them all together and told them to stop. I marked the circuits and their home-runs on the plans.

Job was done and we were days ahead of schedule. Owner asked me how I was able to save time I gave him a list of changes I had instituted on the job. He flipped when he found out I hadn't followed his 'signature' method. After he calmed down he talked to the HO without directly mentioning the difference. They were very happy. He reconsidered when the finances became clear. He had done the job electrically as well or better than his norm, the HOs were very happy as I had thrown them some amenities, the BIs were happy with the job and quality, the GC was happy and the company had made more money doing it.

Simply his 'signature' only impressed himself. Any electrician worth his salt could easily work with the panel schedule provided. Odds are that in thirty years, as is typical, the panel schedule will bear little resemblance to reality. The paper itself will likely be missing. In a relatively short time it won't matter.

Years later I worked again for the same company and their 'signature' had been shifted to something most HOs cared about. The labeling fetish had ended. If anything the customers seemed happier than ever.

Interesting enough I have worked on some overly documented houses. The circuit numbers printed under the box covers didn't survive the first repainting. Even the nice plastic labels plastered on the breakers were out of order as they had added a 240v circuit to allow installation of a window unit. The office, with its computers, devices and southern exposure was running warm.

The electrician had added a breaker and had, intelligently, grouped it with the others two-pole units down one side. This threw off the numbering system. Excessive labeling is fine for as long as it remains accurate. Once it is out of date it just gets in the way.

Time is money and there are more than enough places to meaningfully increase quality. Labeling everything, beyond simple and practical standards, isn't one of them. It's a house not the space shuttle. People working on the electrical system are expected to be trained and capable of finding a breaker in good time with only simple descriptions. Without having their hand held and needing it spelled out.

(post #100082, reply #26 of 36)

I agree.  I am a foreman working for a large electrical contracting busiiness and a lot of what "professionals" do is junk.


Offered to help the plumbing foreman onour  job do his basement for free in return for some help with the work and he would buy some steaks to grill out while we worked.  Figured I could trade off a little labor.  That was back in September.


He hired a "buddy" who is also certified electrician to do this and it still isn't done...it's a mess...and he wants to use his basement for the super bowl...and it ain't gonna be cheap for me to go back and fix what I essentially offered to do right for free in the first place...


With electrical stuff there are some competent DIYers that do as well as some of the pro's.  But I would also second the advice to hire someone if  one doesn't know what they are doing.


Worst fix I ever did was on a house a church group bought for use in helping homeless women.  Some DIY had wired everything in the house with 22 speaker wire.


Chris

(post #100082, reply #27 of 36)

I agree. 


I'm not a licensed electrician -- just a hard-core DIY-'er.  I've done a vast amount of electrical work and even some electricians have commented on how nice and neat my work is.  I make sure I know what type of circuit I'm working on (i.e. 15 or 20 amp) and make sure I'm using the appropriate guage wire (14/2 for 15-amp circuits and 12/2 for 20 amp).  I also staple new romex to framing every 3-4 feet and use plastic insulated metal staples.  I have 200-amp service and it's grounded.  I make sure every metal box or fixture I install is grounded and that there's 6-inches of free conductor coming out of the boxes.  I wrap all switches and receptacles with black electrical tape and even wrap tape around wire-nuts when making splices inside boxes.  No "back-stabbing" for me, either -- I go the extra step and loop the wire clockwise around all screw terminals. 


I've read several books on electrical work and if I have any question on whether something's safe or legal, I call my electrician (whom I leave the "bigger" jobs for).  Or, I'll ask a question here.  I've gotten lots of great advice from the electricians here!!


If you do your homework, there's no reason a careful homeowner can't do a good deal of electrical work himself/herself.  That includes work inside the service panel!  Just make sure you turn the power off!! 


 


 


Toolfanatic (a.k.a. The man formerly known as "Toolfreak")

(post #100082, reply #4 of 36)

BTW, if there are two many the wires need to be derated because of the heat buildup.

Don't have time to give the specific numbers.

. William the Geezer, the sequel to Billy the Kid - Shoe

(post #100082, reply #10 of 36)

I hope Bill Hartman, Bill Hartman will correct me if I am wrong but I though a given junction box could only have connection made in it from one breaker.  Sure multiple circuits could run through a coduit but that would just be wires passing through a box with connections from another circuit.


I worked on my kitchen light switch today.  Would you believe the disposer switch in a house wired by professional union electrician was on a different breaker?


Conduit is expensive, so why wouldn't you want to get the most out of it?


 


Big Macs - 99 cents
Big Macs - 99 cents

(post #100082, reply #15 of 36)

Dave said: "I worked on my kitchen light switch today. Would you believe the disposer switch in a house wired by professional union electrician was on a different breaker?"

YES! The NEC says lights and appliance circuits in the kitchen need to be on different breakers. Some people put the dispose on a separate breaker, I usually group the dishwasher and disposer on the same breaker if they are close, and usually they are because they both use the same kitchen sink. Also, junction boxes can have many circuits in them, not just fed from one breaker.

Be careful out there, use testers to see the invisable electricity. And remember high voltage will reach out and touch you, no contact needed. Consider all wires hot,even neutrals and ground, until tested.

Frank DuVal

You can never make something foolproof because fools are so ingenious.
Frank DuVal

(post #100082, reply #16 of 36)

CEC says that ALL appliances must be on their own circuit. This means;


fridge, dishwasher, garborator, instant hot water, microwave, etc. etc.. each must have it's own separated breaker


This is one of the reasons that so many circuits are required in the panels nowadays. We used to get away with a 24 cct panel; 32 cct was half empty... now; 42 cct is a minimum.


Dang them paper pushers!! (VBG)


 


locolobo


Edmonton, Alberta, Canada

(post #100082, reply #23 of 36)

Since the subject is 120/240 Vac , please explain how:


high voltage will reach out and touch you, no contact needed for 120/240?


 


 


 


edit FWIW for safety reference, 4160V can 'reach out' about 1/8 inch, 13.9kV about 7/16".  Did personally get hit in 1967 with 3.2kV from a 1 A capable source, chance ("luck") was good as fibrillation only starts if a momentary contact is maintained during the heart's T wave. Kinda in shock for about 5 minutes though, always VERY careful since then with anything 460 or over; however, still do lots of stuff around the house with live circuits when not wet and sure of no open cuts or metal splinters in fingers.  Lotta details to know, as they say, don't try this at home? .


Edited 12/31/2005 9:40 pm ET by junkhound