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Why NOT to use #12 wire for lighting circuits

theoldwizard1

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If any of you have watched any of the YouTube channel "Pure Living for Life" you know the couple are building their own house and a stumbling (many would say fumbling) along with issues that professionals or experienced DIYer would never have, all of their own making !

Today's Episode, Pulling wire through SIP chases ***** ! is a classic example. Somewhere along the line, Jesse decided that #12 NM-B was a good choice for lighting circuits ! Besides being a waste of money, it is a pain in the **** when you have to pull MULTIPLE cables through a 1" (?) chase !

He has one chase that has a 3 gang switch box and an outlet. Two of the switches are 3 ways. I don't understand why he has FIVE cables in that chase ! (The inspector said he would approve it only because most of the loads are "lighting only".) There are several different ways to achieve the same goal with less cables.
 
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SGKent

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It's reality TV. My brother was on a HGTV remake of a yard a few years back. He went home and never came back because he felt it was so phony. The show hosts were using an auger off camera to dig the plant holes in clay and rock, drop a plant in and throw some bark and mulch around it. The videos showed before, and then someone adjusting bark/mulch with the after shot. He figured every plant probably died in the first couple months but it made for nice video shots. Running power, cutting and nailing on some of these programs are all rookie stuff.
 

dutchgray

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Its the you don't know what you don't know situation, at least they are doing something, by the time they are done they will hopefully have learnt something and the next time they will be better, well some never learn to stop reinventing the wheel and stick to tried and true.
 

seanc_mt

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I used 12/2 for all my lighting circuits... Not that much harder to work with and I can run all my lights on one breaker with each light switch feeding the next. Works for me.
 
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theoldwizard1

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I used 12/2 for all my lighting circuits... Not that much harder to work with and I can run all my lights on one breaker with each light switch feeding the next. Works for me.

The guy is wiring a basement garage and some outside lights. I'm sure he is using 4' LED shop lights inside and like likely outside. One 15A circuit and #14 NM-B would easily cover all of that lighting load.
 

BD1

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I used all 12 gauge when I did my house. Didn't want to mess with 14 and 12.
I didn't have any issues with all 12 gauge.


Sent from my iPhone using Tapatalk
 

Innovate1

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In Illinois you aren't allowed to use 14. You have to use 12 on 15A and 20A circuits. At least that was the rule 15 years ago when I built and I doubt it has changed. True, 14 is cheaper but other than being a bit larger there really is nothing wrong with running larger wire than needed.
 

Jim greengo

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Pain in the *** to work with,takes up more room in boxes.
I run a seperate circuit for each room I wire,makes life easier to chase things down/not overload anything.
Except for kitchens and bath of course,multiple circuits.
For garages I generally run a 15a circuit for lights,multiple 20s for outlets.
 

BillK

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I used 12 on everything when I built my garage. I had no problem with it but it is all very straightforward without a bunch of multiple circuits in boxes etc.
 

matt_i

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Why NOT to use #12 wire for lighting circuits?

Because if you were building 100 houses you'd be down a free boat or sports car.
 

pbon

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For the diyer who has plenty of room to work with, thicker wire may not matter. And if to use 12 for outlets and 14 for lights he would buy more cable, the cost could be the same or less depending on the lengths needed. It could possibly be cheaper to just buy one big roll of 12.

I bought big rolls of 10, 12, 14 and 18 (led dimmer) and used most of everything, but my rough calculations showed I would need it to do lights and outlets in a 4 story 23x29 carriage house with 2 finished floors as my shop and storage.
 
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Notgrownup

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I used 12/2 in my Shop for everything Standard. I did ask a licensed electrician before if it was real overkill and he said maybe in some cases but not that much.
 

Earp69

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Still not sure why NOT to other than your opinion. If I have a lighting circuit with a 16 amp load, why not run 12/2 with a single 20 amp breaker vs 14/2 and two 15 amp breakers? Maybe this thread needs retitled to why you shouldn't use 12/2 for lighting circuits in wizards world
 

Stuart in MN

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It costs more and depending on the particular situation it may be more difficult to install, but functionally there's no problem with using larger wire. For a homeowner working on a single project it's not that big a deal.
 

seanc_mt

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Why NOT to use #12 wire for lighting circuits?

Because if you were building 100 houses you'd be down a free boat or sports car.

Over 10k feet it would be a savings of $800 so meh.... If I'm a contractor building 100 houses and I want a new car I'll just factor it in.... ;)
 

mobiledynamics

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My 1st house I did it all in 12.....learned that 14 is just much nicer to work with on both the lighting and switch boxes than 12 !

Larger is not always better.
 

grounded-b

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If any of you have watched any of the YouTube channel "Pure Living for Life" you know the couple are building their own house and a stumbling (many would say fumbling) along with issues that professionals or experienced DIYer would never have, all of their own making !

I agree. Plus his comprehension of circuit wiring ***** !!

He went through a 1000' spool of 12-2 Romex in the basement/garage, and is still not finished.

He is definitely wiring circuits in a loop, and I wouldn't doubt he has some hots and neutrals fed at two points.

Steve
 

grounded-b

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#12 AWG use up 2.25 cu inches of box volume, compared to #14 AWG, which uses 2.0 cu inches.

You need MUCH larger boxes, when you wire with #12 AWG

I am sure Jesse's boxes are way over filled. Especially that 3 gang switch box next to the man door of the garage/basement

Steve
 
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rd65

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I wired my shop w/ #12 because I got a couple spools from my father in law and I didn't want to buy extra wire. Was purely a cost saving decision. I did screw up with the single boxes for my outlets. That #12 wires fills things up in a hurry.
 

Falcon67

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I used #12 on everything and it's a PITA in a 4" box with a couple of runs and switch legs. Now that every fixture is LED, if I had a do-over all the lighting would be 14.

I picked up a bunch of 2x4 flat panel LED grid lights from a project at work - replaced under warranty as some were failing - and the power wires are like 16 gauge for the panels.
 
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yeldogt

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Agreed ... 14 is better in my opinion for lighting ... actually with loads dropping except in kitchens. What.s really being used ?

prior to the modern code that increased outlet numbers to eliminate extension cords -- 12G wire and 20amp circuits actually increased fire risk when extension cords are used.

When I first started building -- I had this more is better attitude. 12g wire is a ***** when doing lots of complex lighting .. no room in the boxes
 

tonyciambrone

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Where I am we use conduit... and most the time I buy wire it doesn't make sense for me to buy smaller quantities to 14 and 12 separately.. This higher price of small spools negates any savings.

Using romex,I guess I can see the point.

What is really stupid here is that old Jesse should have HVAC and plumbing done first, then insulated the garage ceiling, then covered everything in a very, very fire resistant material, and run exposed work on the surface of the garage.

It is a garage afterall. Then there is no cutting chases and hot knifing the sips, no mud rings or measuring box depth, no thousand runs of romex etc.

The thing is the guy doesn't know much about anything, and refuses to take criticism. Makes for a hard life. Check out the pure living for life subreddit, it's pretty brutal, but honest.
 

Bretny

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Purelife for living is a joke of a youtube channel. I stopped watching them and wrangler star and a few others years ago.

I also used #12 wire for lighting...but i wasnt trying to pull it through conduit.
 

tab2

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Wow just started watching this video. I don't even have words for how uninformed this guy is about basic construction.
 

2level

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I used #12 Romex for most of my garage lighting circuits to allow for easy conversion to 20amp receptacles.
 

sberry

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I use 14. So much easier to work and make a quality install especially if using cable. Piped and stranded isn't so bad. I like some easy wire, use 2 conductor from switchbox to switchbox on new work and 3 conductor to fixtures and if I do use a single cable switch loop usually use 3 conductor in remodel. People change their mind, maybe they later want to add auto equipment or extend the circuit.
 

James-W

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Still not sure why NOT to other than your opinion. If I have a lighting circuit with a 16 amp load, why not run 12/2 with a single 20 amp breaker vs 14/2 and two 15 amp breakers? Maybe this thread needs retitled to why you shouldn't use 12/2 for lighting circuits in wizards world
I suppose you COULD have a lighting circuit with a 16 amp draw, but I can't say as I have ever seen one. I mean, most lighting these days are LED, or at the most CFL, and both of those types of lights use very little power. I can't imagine having enough of those types of lights on a single circuit in order to draw 16 amps. I am sure you could do it, but I wonder how many lights would it take to draw 16 amps?
 

woodzy

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In 1999 I built my shop - I use 12 gauge for all lighting / outlets - it is a 30 x 64 2 story building. I have plenty of outlets and power at any outlet. Fast forward 15 years, my two sons are now certified electricians in the field. I'm building a new home on the same lot and tell them I'm going to run 12 gauge to all the outlets and lights - they tell me no way - I must be nuts. 14 gauge is much easier to work with and in a home you really don't have that large power requirements at any one outlet. In the places you do, they require you to use 12 gauge like the bathrooms, kitchens, laundry rooms, garage, and outside.

So, did all the lighting in 14 (all LED's), all the outlets in 14 except where we could not, and it was very easy. As I was doing the outlets, I hated doing all the 12 gauge but the 14 were a breeze. I think this is the first time in my life I took advice from my children. :)

I think it is a personal preference - but a few extra feet of wire or a few extra 15 amp breakers doesn't cost much in the grand scheme of things. It's been 5 years and have never tripped a breaker from an overload.

And I would never use stranded wire - stick to romex..
 
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theoldwizard1

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The key is 12 gauge stranded not solid If 12g is preferred.

Stranded requires conduit. Conduit increases costs (especially on labor) and is rarely used in residential situations except when required by code.

Stranded then has the issues of termination.............

No issue is you use better quality switches and receptacles that have side clamps.
 
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theoldwizard1

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... and if I do use a single cable switch loop usually use 3 conductor in remodel. People change their mind, maybe they later want to add auto equipment or extend the circuit.

Good idea and if not in the current NEC it is proposed for the next.
 

Bopbop

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Last year when I had a friend who owns a commercial electrical construction wire my shop he said that he only uses 12 guage wire for his lighting circuits. He did not have 14 on his trucks or in stock. His idea was he had done to many service calls were the issue was on the receptacles circuits was somebody had put 14 guage on a 20 amp circuit and was overloading the circuit.
The cost difference between the 2 is cheap when you consider the cost of burning down the place. Just my thought, I have always been told I overbuilt and over think things but I sleep good at night.
 

sberry

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One thing about stocking trucks, there isn't room for everything, can do the same work with 12 as 14. I was in a panel a while back and it had confused the maint guys due to the fact some of the 12 wire had 15 on them, multi wire circuits and very congested. Reason the 12 had 15's was at a jbox outside the panel he had it hooked to old 14 wire circuits.
The installer was a master,,, but probably had 1 wire in 3 conductor on the truck. Way different than projects where stock is on the job, I just wire a house this week, all recepts on 20, all lights on 14, so much easier, some cheaper, so much better making terminations and having the fixtures on 14/15 cant hurt,,, lowers the potential fault current quite a bit.
 

sberry

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Good idea and if not in the current NEC it is proposed for the next.
I have a system worked out for this, its easy, its minor cost to future proof a little and its one I have used a couple times. Most of that effort ids useless but this is one place it cost so little and makes it so much easier to add a minor fixture down the line. Find any fixture box and connect another wire to it, not for new general recepts but for lights etc.
I am just finishing a house now, about 2 days left, maybe a little more. Complete rewire.
 
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