Growroom Electricity and Wiring

[rives]

the space i'm in currently has a 240 50 amp service coming into it. i thought it was perfect for my 8 light controller. however, the gauge of wire being used is 11. so given the gauge, i only really have around max 4000 watts to use even if the breaker is 50 amps? correct?

i realize i need to replace the wire with gauge 6 or 8 at least if i want to draw more power. the problem is i do not have access to the main breaker switch. i have access to the 50 amp breaker and the rest of the breakers in the space, but i do not have access to the central breaker and therefore cannot kill all power.

is there a way to rewire without turning off central breaker safely? i know you can extend the circuit, splicing two wires together, by just turning off the breaker of the circuit you're working on? but when you rewire from the breaker box is it completely necessary for power to off completely?

You must have a typo - there is no 11 gauge wire. If you meant 10, it is only rated for 30 amps and needs to be changed asap. 8 is good for 40 amps, and 6 for 60.

If you work carefully, there should not be a need to kill the power to the whole panel. You can turn off the 50 amp breaker, remove the existing wire, and replace it with a larger conductor. Make sure that you don't brush up against anything that is still energized, or shut off the other breakers in the panel and the only thing that will still be hot are the busses and the main lugs. A technique used by electricians when doing hot work is to keep your left hand in your pocket and only use your right. If you get hit, this helps keep the current from flowing through your heart. Also, a pair of new, clean (so they don't have conductive material imbedded in them), snug-fitting leather driver's gloves are a good insulator.

 

[smoke_tayo]

the 50 amp breaker is alone on one side of the panel so it shouldn't be too difficult then. getting some leather driver's gloves stat!

rives, thank you so much for your reply. you're a great help!

i was perplexed by the 11. those are the only numbers i saw on the wire coming from the 50 amp service, other than 600v vwl. basically what was imprinted was "600v vwl 11" over and over. any idea what gauge it might be based on that?

 

[rives]

the 50 amp breaker is alone on one side of the panel so it shouldn't be too difficult then. getting some leather driver's gloves stat!

rives, thank you so much for your reply. you're a great help!

i was perplexed by the 11. those are the only numbers i saw on the wire coming from the 50 amp service, other than 600v vwl. basically what was imprinted was "600v vwl 11" over and over. any idea what gauge it might be based on that?

No idea from that. If that is all that you can find printed and it repeats several times, you might try the back side of the wire to see if something else is imprinted on it that you haven't noticed. The other thing that you could do is get some samples of different gauge wires and compare them, or if you have a set of dial calipers you could measure the wire (the copper only, not the insulated portion) and look up the diameter.

 

[smoke_tayo]

before i do any work, i just wanted to confirm the wiring of the 240 50 amp breaker. so the two hot leads go into the two pole circuit breaker and the white wire is connected to the ground/neutral bar.

this bar where the ground goes is not hot, correct? and is completely different than the busses and main lugs?

if i shut off all breakers in the box, only touch the 50 amp breaker and the ground bar, then i am good, right? just wanted to be extra careful and confirm. thanks a bunch.

 

[rives]

before i do any work, i just wanted to confirm the wiring of the 240 50 amp breaker. so the two hot leads go into the two pole circuit breaker and the white wire is connected to the ground/neutral bar.

Correct. If this is a main panel (from your above description though, it sounds like a sub-panel), then the grounds and the neutrals are on the same buss. If it is a sub, then they should be isolated from one another and only bonded together back at the main. If this is the case, the difference between the two should be very evident - the ground buss will have uninsulated wires terminated on it and the neutral buss will have white wires connected.

this bar where the ground goes is not hot, correct? and is completely different than the busses and main lugs?

No, the ground buss should not be hot, and it is completely different from the other busses and main lugs. The ground buss may be hot to ground if the system is inadequately grounded, but if you kill all of the breakers in the box, that should take care of it.

if i shut off all breakers in the box, only touch the 50 amp breaker and the ground bar, then i am good, right? just wanted to be extra careful and confirm. thanks a bunch.

See above, yes, you've got it. If you could put up a picture, it would help.

 

[smoke_tayo]

240 wiring

240 wiring

hi rives, attached is a picture of the subpanel. the two hot reds are going into the 50 amp on the left and the white ground goes to that bar on the right. i was able to find out the gauge of the wires when i opened the panel. the reds are 10 gauge and the white is 12 gauge.

https://www.icmag.com/ic/picture.php?albumid=35570&pictureid=840989

i think the hardest part will be fishing the wire through the conduit. there are 4 turns over about a 20 foot run. the conduit is 3/4 inch. how hard will it be to fish 3 6 guages or 3 8 gauges?

i haven't quite settled on a light configuration yet. i have an eight light controller and am debating between 4 1000w and 4 600w or 2 1000w and 6 600w. for the first configuration, at 6400w i definitely need to switch out the wire to at least an 8 gauge.

however the second configuration would only pull a total of 5600w. if i changed out the breaker to a 30 amp, i could safely run the 5600w off the 8 light controller with 10 gauge hots and 12 gauge ground, correct? and if i wanted to extend the 10 gauge off the 30 amp by 10 feet or so, would it be alright to use 8 gauge (or do i have to size to 10 gauge wire)?

its probably my best bet to just change it all out to 6 gauge future upgrades in lighting won't be a problem, but the 6 gauge is pretty darn expensive and it looks like fishing through the conduit is going to be a pain. kinda dreading spending hours trying to fish given its my first time and such. plus all the fishing equipment seemed costly. though i'm probably never going to run all 8kw through the controller so perhaps 8 gauge would be best.

any tips or tricks on fishing wire? will i have an easier time with 8 gauge?

 

[rives]

First of all, let's address grounding. If your conduit is pvc, you need to be carrying a ground wire with the other conductors. If it is rigid or EMT, it isn't required but is recommended (particularly with EMT), and still requires approved lockrings, bonding bushings if going through a concentric knockout, etc. A separate ground wire is always a good idea. The ground wire can be reduced one wire size (if you are feeding the panel with #6, you can use a #8 ground), and can be bare or green. Bare wire will reduce the size of the wire bundle, so it may be easier to pull, but a green THHN-insulated wire is very slippery and probably easier to pull even though it will have a larger diameter.

360 degrees of bends is the maximum allowed in conduit between openings, so if your bends are 90s, you are right at the maximum allowable. If the bends are true electrical 90's (roughly an 8" radius), then with that short of a run you shouldn't have any problem if you have someone feeding the wire into the conduit while you pull. Feeding the wire is the big trick when making a pull - it can ease the task immeasurably or make it impossible. Lay the wires out on the floor, remove all of the tangles and twists, group them in a smooth bundle, and lightly push them into the opening while pulling from the other end. A little bit of pulling soap (lubricant) will make it go more easily, but it needs to be a product designed for this so that it won't degrade the insulation over time.

I have seen people use 90s that are plumbing fittings (+/- 1" radius), not knowing that they weren't appropriate. If that is what you have, tear the pipe out and start over - you will never get the wire in.

(4) #6 THHN-insulated wires are the maximum allowable for 3/4" conduit, and other types of insulation won't fit. For this installation, you could use (3) #6 and (1) #8. If you go with 8 gauge, the ground wire could be a #10, and the circuit should be fused at 40 amps. Yes, #8 would be easier to pull.

The easiest way for you to fish the wire in would be to use one of your existing wires to pull in the new bundle. If you strip the insulation back on both wires (the existing one selected to use as a pull wire and one out of the new bundle), it will reduce the diameter and make it easier to connect them. If you fold the stripped portion back over itself (180 degrees) and twist the wire around itself, it will form a loop. Do this with both wires, with the loops inter-connected, and then smoothly tape over them with electrical tape. This keeps the diameter down and makes a strong enough connection to pull with. The remaining wires need to be taped to the one that is attached to the pull wire, with the tape wrap going long enough to keep them in place while pulling.

The new wire bundle can have a loop of tape (just a couple of wraps) around it every few feet, holding the wires in a smooth bundle and easing the feeding task. If you leave the end of the tape hanging (before breaking the tape off, spin the roll so that the tape twists up, and then break it off so this twisted part stays with the wire. This will keep it from sticking down and give you a "handle" to pull the tape off with). The tape should be removed as the wire goes into the pipe in case you need to use one of these wires for a pull wire in the future.

This may be hard to visualize from my description. If so, I can mock it up and shoot some pictures, but it will have to be later this afternoon.

 

[smoke_tayo]

the conduit is metal. and i believe the 90s are just bent? i'll have to double check. currently the wiring is done with 3 wires. i'm not sure why i need 4 in your recommended set up? is it because 2 will be hot, 1 neutral and 1 ground? neutral and ground will go to same bar in pic?

i'm having a hard time visualizing the fishing explanation. the 3/4 conduit only houses the 2 10 gauges and the 1 12 at the moment. so i leave those wires in while i fish the new wires? and i tear back the insulation? how much do i tear back? a mock up would be great.

def need to make sure they aren't plumbing fittings, because if thats the case then i'll have to stick with the 10 gauge because i don't have the option to lay new conduit.

 

[rives]

the conduit is metal. and i believe the 90s are just bent? i'll have to double check. currently the wiring is done with 3 wires. i'm not sure why i need 4 in your recommended set up? is it because 2 will be hot, 1 neutral and 1 ground? neutral and ground will go to same bar in pic?

If they were done with a bender then they will be fine. Yes, 4 wires is for (2) hot legs, (1) neutral and (1) ground wire. The neutrals and the grounds are supposed to be on different busses except at the main panel, where they are bonded together. If the conduit is metal, and it is attached to the panels at both ends with the appropriate fittings and it has good mechanical joints between pieces, then a ground wire is not required. Carrying the ground with you insures that you have a good ground in the event that something goes awry, like the emt falling apart at the fittings or a concentric knockout breaking out of the enclosure.

i'm having a hard time visualizing the fishing explanation. the 3/4 conduit only houses the 2 10 gauges and the 1 12 at the moment. so i leave those wires in while i fish the new wires? and i tear back the insulation? how much do i tear back? a mock up would be great.

I will take some pictures and post them for you. You would leave whichever wire that is the longest in the pipe to use as a pull wire, and pull the other two out. Tie off the one that you want to leave so that it doesn't come out with the other two, or if someone left them taped together, simply pull out all three at the same time as you pull in the wire - you will use the existing wires as a fishtape. Strip the insulation off of the wire for about 8"-12", and make a loop with it. Do the same with one of the new wires after passing the stripped end through the loop that you created in the other wire.

 

[smoke_tayo]

the subpanel seems to only have one bar as per picture. how do i know if it is a ground or neutral bar?

in any case the wire will be enclosed in metal and secured so i can get away with using only 3 wires then.

i think i get it now. this seems a lot more manageable now. so some fishing lube is all i need to buy then. to think i was going to buy an 80 buck fishtape!

such a great help rives. thanks so much for being patient with all my questions.

 

[rives]

how do i know if it is a ground or neutral bar?

From the picture, it is a neutral buss. You can buy optional busses to install a ground buss in there. If you bond the two together anywhere but at the main, you can create ground loops, which will raise hell with sensitive electronics.




Here are some pictures -

Strip the wire and make a loop -

Do the same with the other wire -

Tape on the additional wires, staggering the ends -

Tape your bundle so that the tape is easy to remove as it is pulled in -

Tape the junction between the pull wire and the new bundle -

Fully taped (almost). I only put one layer on so that you could see what was going on. A few layers of tape, particularly over the staggered ends of the additional wires on the new bundle, will make it easier to pull -

 

[chase]

Subscribed , got to learn this subject . Good stuff!!!

 

[Mountain High]

Hey Rives... I could use some electrical knowledge from you. I'm planning on wiring up my MLC 4XT to my dryer receptacle in the next couple days.

I don't have easy access to my breaker panel. I'm thinking it would be easiest to run some 10 gauge wire from the MLC 4XT and ad on a 30 amp dryer plug and plug it in. Laundry will only happen when lights are off. The problem I have is the MLC 4XT is made for 10/2, and the existing dryer receptacle is a 4 pin requiring 10/3. Is it possible to run 10/2 from the MLC 4XT to a 4 pin dryer plug and just connect the two hot wires and the ground to the plug and leave the neutral connection without a wire?

 

[Mountain High]

OR... the installation instructions says "Some Range or Dryer Cables have a white wire. They can be used on the MLC." So, how do you do this, is somewhere to connect the white "neutral" wire inside the MLC that I don't know about?

 

[rives]

Hey Rives... I could use some electrical knowledge from you. I'm planning on wiring up my MLC 4XT to my dryer receptacle in the next couple days.

I don't have easy access to my breaker panel. I'm thinking it would be easiest to run some 10 gauge wire from the MLC 4XT and ad on a 30 amp dryer plug and plug it in. Laundry will only happen when lights are off. The problem I have is the MLC 4XT is made for 10/2, and the existing dryer receptacle is a 4 pin requiring 10/3. Is it possible to run 10/2 from the MLC 4XT to a 4 pin dryer plug and just connect the two hot wires and the ground to the plug and leave the neutral connection without a wire?

In looking at the directions for your controller, it looks like they are getting the neutral from the trigger cable. You could do as you are thinking, and not connect a wire inside the plug or you could carry the 4 wires to the controller and tape off the neutral. The best way to do that is to fold it back onto itself and tape it thoroughly.

Keep in mind that with this arrangement you can easily overload the neutral on the trigger cable if you have too much 120v load - the current will be supplied by the large wires 1/2 the time, and by the small neutral conductor the other 1/2 of the time.

Sorry to hear that you bought CAP - those things scare the shit out of me. They don't meet code, aren't UL approved, and if you have a fire your insurance company will very likely not pay as a result. Those 120/240 "universal" receptacles are some cheap Chinese shit that couldn't be manufactured by a reputable company because they don't conform to NEMA standards. Good luck!

 

[rives]

OR... the installation instructions says "Some Range or Dryer Cables have a white wire. They can be used on the MLC." So, how do you do this, is somewhere to connect the white "neutral" wire inside the MLC that I don't know about?

I looked at the directions again, and don't see any provision for easily using the dryer cable neutral. I also can't see where the black wire from the trigger cable is going - in the upper picture, it appears as though it is going to the bottom of the left-hand receptacle, but the receptacle is wired for 240v and the tie bar is in place to tie both sides of the receptacle together. Can you look in your unit and see where the trigger cable black wire goes?

It appears that you could just tie into the from the trigger cable by cutting it off and wire-nutting it to your dryer-cable neutral or, preferably, crimping a 1/4" quick-slide connector on and putting it on the other terminal on the relay.

How much 120v load are you planning on using? Are your ballasts all wired for 240v?

I would recommend that you buy some quality 6-15 or 6-20 receptacles and replace those cheap fire-starters in your panel. The directions for the controller leave a lot to be desired - they state that "3) 30 amps of power require a wire size of at least 8 awg." (It doesn't - #10 is rated for 30 amps and #8 for 40), and then the following line says "Two wire cable with ground (10/2) is recommended".


http://www.randmsupply.com/images/link/MLC-4XTInstructions.pdf

 

[Mountain High]

Hey Rives, I called and talked to R&M supply about it. They told me to wire up the 4 prong plug with the 10/3 and just cut and tape the white neutral wire at the MLC. This is probably what I need to do.

The 120v for entire room runs a 400MH, 3 inline fans, pumps and other misc. Is this what you're asking? I will be running 2x 1000 watt ballasts on the MLC and yes they are 240 or 120 ballast and I have run them at 240v with this MLC before that I wired to my baseboard heater at my old place. Lights were hot enough so I never used the baseboard heat for heat.

I will look inside the unit when I get home tonight. Try to see where that black wire goes. I know there are black wires that go to a green light on the front of the unit to show when lights go on. The timer runs on a separate 120v plug.

Thanks for the tip about CAP. Now I won't be sleeping at night until that's fixed.

 

[rives]

The reason that I was asking about how much load you had on the 120v portion was to see if you were in danger of overloading the small neutral in the trigger cable. Many people are under the impression that the hot wire supplies all of the current, the device uses it all up, and the neutral is just there to complete the circuit. This is incorrect - alternating current flips polarity back-and-forth 60 times a second (60 Hz), so the neutral supplies just as much current as the hot wire. This misunderstanding can lead to dangerously overloaded neutrals in circuits where the neutral is undersized.

 

[Mountain High]

here are a few angles for ya...

 

[rives]

here are a few angles for ya...

???

How weird - didn't see any of your links until I quoted you, and they were in the quote.

*edit* Even when I c&p your links into the browser, no image shows up, and your links are still invisible. Is your album made public?