Please be advised that decades ago the NEC did approve using a dedicated branch circuit to the dryer or range that used only three wires receptacle to supply 240/120 volts to the dryer and range, and bonding the neutral to the chassis ground inside the dryer or range was allowed. However that is no longer allowed by NEC in new circuit installation. Now a new circuit must have four wires (two hot wires, one neutral wire, one grounding wire) for 240/120 volts dryer and range, and cannot bond the chassis ground to neutral.
Experienced Electrician! Here to Answer Any and All Growroom Electrical Questions
- Thread starter bricktown73
- Start date
contraptionated
New Member
I already elaborated. Old subject but thanks anyway. I already stated that its to prevent a parallel pathway to ground in the incident of short circuit current.
contraptionated
New Member
Who asked this question? With all due respect, and I do give you respect because you put in time and effort to explain things, but this is only a loosely related example of when the neutral and grounding conductor should not be interchanged or interconnected with one another. Even though it is common for a grower to re-purpose a dryer circuit for a sub-panel feeder and they might be curious as to how and why it was wired that way or if they could do the same thing with the neutral (if it was even used as a grounding path to begin with ) it still is irrelevant and verbose. This question was already answered and you went off on 2 tangents.
The last tangent going off of the first. That runs the thread askew and could only leave people scratching their heads when you mention a dryer that nobody asked about.
legallyflying
Well-Known Member
Sparky fight!!!
Sorry to disappoint you, but there isn't going to be a sparky fight today, as none of my posts were intended to debate anything. I was merely trying to explain things to you in laymen's terms rather than leaving you solely reliant on one language.
legallyflying
Well-Known Member
Awwww 
.
I do appreciate it. I'm not a complete layman but your explanation was easier to follow than whats his nuts. Which you can see, it actually took him several posts to answer my question. Your explanation helped allot actually.
So just for shits and giggles. What does happen if you have parallel grounds?
. I do appreciate it. I'm not a complete layman but your explanation was easier to follow than whats his nuts. Which you can see, it actually took him several posts to answer my question. Your explanation helped allot actually.
So just for shits and giggles. What does happen if you have parallel grounds?
The words "parallel grounds" and the words "parallel pathways" can take on two different meanings when taken out of contexts. Should someone illegally or inadvertently bond the neutral wires to the grounding wires in a sub-panel, I'll leave you with this food for thought: Current flowing through a neutral conductor will create an impedance in the wire. The impedance will increase with an increase in current flow, and the impedance will increase with a decrease in wire diameter. This impedance in the neutral wire will create a voltage difference between neutral and earth ground. This could be only a few volts or it could be several volts that is enough to shock you.Awwww
I do appreciate it. I'm not a complete layman but your explanation was easier to follow than whats his nuts. Which you can see, it actually took him several posts to answer my question. Your explanation helped allot actually.
So just for shits and giggles. What does happen if you have parallel grounds?
contraptionated
New Member
If I tell you not to do something a certain way and you don't understand the explanation because it was terse that would be the problem of the readers comprehension skills. If I open the code book and complain that it gives me the shortest explanation possible by using the most specific and correct English, than I would need to open a dictionary.
Brevity for the sake of sanity.Less words=efficiency.
Brevity for the sake of sanity.Less words=efficiency.
The first sentence in that paragraph sounds like a perfect description of a "floating grounding system". Why would you not bond the enclosure to the grounding wires? It should be the neutral wires that get isolated from the enclosure. The only example I can think of off the top of my head to have a floating AC grounding system is when the same panel is being used for both AC and DC circuits, to isolate the AC grounding from the DC grounds.
jabolo
Active Member
Hi,
New to this forum and looking for some help on electrical setup.
Im building a pc grow box, have setup the lights - I never did any electrical work before so would like to check if I did it right before I start vegging.
Lights electrical setup (CFL):
I used 3 wall sockets which I fixed to the top of my Pc grow case (a plywood fixed to the 'ceiling', then the wall plugs strapped onto the plywood). The bulbs will go into the wall sockets (via adaptors). The wall sockets are each connected (using the red and black wires inside the white isolating plastic) to a splitter (bought the most heavy duty marked 380V) which then connects to a plug. So I have 3 red and 3 blacks going into splitter, coming out as 1 red and 1 black going into plug. For that part I used a thicker elec wire (one that has red, black as well as copper - earth - wire) as I thought that it would be safer. I also bought heavy duty plugs and extensions. Below is a (very ugly) diagram showing the connections i made.
I have yet to find out how to upload pictures - it says invalid file...
I've taken photos using my phone. I tried to reduce the file size from 2Mb to 89kb taking the pictures again on lower res. but still it says invalid file..... What am i doing wrong?
I have another question regarding ventilation: I have 2 size 120mm fans, and 5 or 6 size 80mm fans and one 40mm one.
Im not sure which combo to use for exhaust:
1) 3 size 80mm fans OR
2) 1 size 120mm fan?
Question 1: Are 3 medium fans more efficient than 1 large(r) fan?
I cant tell the rotation speed but i gather that the Ampage on each fan, is an indication of its max rotation speed, right?
If so, should i use a 0.27A fan rather than a 0.12A one?
Question 2: Should i use fans with higher amp?
Powering the fans:
I understand that my charger amp rating should be higher than my total amp for all fans connected. E.g. 3 fans at 0.12A = 0.36A total; would need a charger with a rating of at least 0.40A (400mA).
Q 3: Is the above correct regarding the amp etc?
Now for the voltage. Fans are at 12V. I got a charger that outputs 12V with Amp rating of 1.25A.
Q 4: Is a 12V charger (or adaptor) good for connecting all my fans (as long as the total Amp is below the adaptor's amp rating) ?
Q 5:What is the effect of using a lower voltage than 12V?
Q 6: As long as my charger's amp rating exceeds my total fan amp rating, does it matter what my charger's voltage is?
I apologise if my questions seem stupid or if i used the wrong terminology. This is my first grow and i really want to get it reasonably right (i am dying for a decent herb since moving in a country with extremely poor supply of quality cannabis).
I have seen quite a few comprehensive and helpful threads and therefore joined this forum to first get advice and hopefully give some advice too at some point.
So thanks in advance for any replies and good luck with your grows!
One.
New to this forum and looking for some help on electrical setup.
Im building a pc grow box, have setup the lights - I never did any electrical work before so would like to check if I did it right before I start vegging.
Lights electrical setup (CFL):
I used 3 wall sockets which I fixed to the top of my Pc grow case (a plywood fixed to the 'ceiling', then the wall plugs strapped onto the plywood). The bulbs will go into the wall sockets (via adaptors). The wall sockets are each connected (using the red and black wires inside the white isolating plastic) to a splitter (bought the most heavy duty marked 380V) which then connects to a plug. So I have 3 red and 3 blacks going into splitter, coming out as 1 red and 1 black going into plug. For that part I used a thicker elec wire (one that has red, black as well as copper - earth - wire) as I thought that it would be safer. I also bought heavy duty plugs and extensions. Below is a (very ugly) diagram showing the connections i made.
I have yet to find out how to upload pictures - it says invalid file...
I've taken photos using my phone. I tried to reduce the file size from 2Mb to 89kb taking the pictures again on lower res. but still it says invalid file..... What am i doing wrong? Question 1a) I would be grateful to anyone who could have a look at the above and tell me if it's okay.
Question 1b) I am using a timer for the lights, the timer had a 13A rating - is this safe to use? All 3 wallsockets holding the bulbs will be connected to the timer.
Question 1b) I am using a timer for the lights, the timer had a 13A rating - is this safe to use? All 3 wallsockets holding the bulbs will be connected to the timer.
I have another question regarding ventilation: I have 2 size 120mm fans, and 5 or 6 size 80mm fans and one 40mm one.
Im not sure which combo to use for exhaust:
1) 3 size 80mm fans OR
2) 1 size 120mm fan?
Question 1: Are 3 medium fans more efficient than 1 large(r) fan?
I cant tell the rotation speed but i gather that the Ampage on each fan, is an indication of its max rotation speed, right?
If so, should i use a 0.27A fan rather than a 0.12A one?
Question 2: Should i use fans with higher amp?
Powering the fans:
I understand that my charger amp rating should be higher than my total amp for all fans connected. E.g. 3 fans at 0.12A = 0.36A total; would need a charger with a rating of at least 0.40A (400mA).
Q 3: Is the above correct regarding the amp etc?
Now for the voltage. Fans are at 12V. I got a charger that outputs 12V with Amp rating of 1.25A.
Q 4: Is a 12V charger (or adaptor) good for connecting all my fans (as long as the total Amp is below the adaptor's amp rating) ?
Q 5:What is the effect of using a lower voltage than 12V?
Q 6: As long as my charger's amp rating exceeds my total fan amp rating, does it matter what my charger's voltage is?
I apologise if my questions seem stupid or if i used the wrong terminology. This is my first grow and i really want to get it reasonably right (i am dying for a decent herb since moving in a country with extremely poor supply of quality cannabis).
I have seen quite a few comprehensive and helpful threads and therefore joined this forum to first get advice and hopefully give some advice too at some point.
So thanks in advance for any replies and good luck with your grows!
One.
contraptionated
New Member
Floating grounding system??? You obviously don't know the code!! You are not supposed to bond the ground ing bar (of a breaker panel) to the enclosure or the neutral bar to the enclosure anywhere except for the main breaker panel. If you comprehended my advice for legallyflying I told her not to bond neither of those things to the enclosure except for at the main breaker panel.The grounding bar at the sub panel (or lighting controller) only gets a grounding wire connection between the main grounding bar (at the main panel) and the sub panel grounding bar in question. To prevent parallel grounding paths. If you don't understand that phrase go look it up in the NEC before you say that it can take on different meanings out of context. Nobody is speaking out of context here! I'm talking about grounding and bonding.
You don't understand the code and you proved it by calling the isolated grounding bar (isolated from the sub panel enclosure) at the sub panel/lighting controller a "floating grounding system". Time for you to step aside son and go study the code book before you put your foot in your mouth again.
Go start brushing up on your Article 250 of the NEC.
P.S. The correct term for what you describe as a "floating grounding system" is "isolated grounding bar". Pretty amazing the way you advise people to isolate the neutral from the metal housing of a dryer (which is correct) but don't understand where and when or why to isolate the grounding wires at a breaker panel.
P.P.S. I'm not superhuman, but I'm infallible when it comes to how and when to implement the NEC. At best you can agree with my electrical advice and stand correct. Why disagree when you will always be wrong??
legallyflying
Well-Known Member
Ummm I am not a her. I'm a him. Is it wrong to want to fuck your avatar?
joe macclennan
Well-Known Member
It would be wrong to want to fuck my avatar but I would certainly like some time alone with the chick in yours
jus sayin.........
contraptionated
New Member
You should house the duplex receptacles in surface mountable single gang boxes (aka handi boxes). This way the receptacles are securely fastened and incidental contact with live parts isn't possible. Try to use romex squeeze connectors or better yet rubber cord connectors to route the 120 volt line through each single gang receptacle box. The receptacles will be wired in parallel, of course.Hi,
New to this forum and looking for some help on electrical setup.
Im building a pc grow box, have setup the lights - I never did any electrical work before so would like to check if I did it right before I start vegging.
Lights electrical setup (CFL):
I used 3 wall sockets which I fixed to the top of my Pc grow case (a plywood fixed to the 'ceiling', then the wall plugs strapped onto the plywood). The bulbs will go into the wall sockets (via adaptors). The wall sockets are each connected (using the red and black wires inside the white isolating plastic) to a splitter (bought the most heavy duty marked 380V) which then connects to a plug. So I have 3 red and 3 blacks going into splitter, coming out as 1 red and 1 black going into plug. For that part I used a thicker elec wire (one that has red, black as well as copper - earth - wire) as I thought that it would be safer. I also bought heavy duty plugs and extensions. Below is a (very ugly) diagram showing the connections i made.
I have yet to find out how to upload pictures - it says invalid file...
View attachment 2702626
Question 1a) I would be grateful to anyone who could have a look at the above and tell me if it's okay.
Question 1b) I am using a timer for the lights, the timer had a 13A rating - is this safe to use? All 3 wallsockets holding the bulbs will be connected to the timer.
I have another question regarding ventilation: I have 2 size 120mm fans, and 5 or 6 size 80mm fans and one 40mm one.
Im not sure which combo to use for exhaust:
1) 3 size 80mm fans OR
2) 1 size 120mm fan?
Question 1: Are 3 medium fans more efficient than 1 large(r) fan?
I cant tell the rotation speed but i gather that the Ampage on each fan, is an indication of its max rotation speed, right?
If so, should i use a 0.27A fan rather than a 0.12A one?
Question 2: Should i use fans with higher amp?
Powering the fans:
I understand that my charger amp rating should be higher than my total amp for all fans connected. E.g. 3 fans at 0.12A = 0.36A total; would need a charger with a rating of at least 0.40A (400mA).
Q 3: Is the above correct regarding the amp etc?
Now for the voltage. Fans are at 12V. I got a charger that outputs 12V with Amp rating of 1.25A.
Q 4: Is a 12V charger (or adaptor) good for connecting all my fans (as long as the total Amp is below the adaptor's amp rating) ?
Q 5:What is the effect of using a lower voltage than 12V?
Q 6: As long as my charger's amp rating exceeds my total fan amp rating, does it matter what my charger's voltage is?
I apologise if my questions seem stupid or if i used the wrong terminology. This is my first grow and i really want to get it reasonably right (i am dying for a decent herb since moving in a country with extremely poor supply of quality cannabis).
I have seen quite a few comprehensive and helpful threads and therefore joined this forum to first get advice and hopefully give some advice too at some point.
So thanks in advance for any replies and good luck with your grows!
One.
Chances are your timer can only handle a 2.6 amp inductive load. 13 amps is probably only if the loads are purely resistive (like a toaster). You are powering inductive loads and the contacts of your timer will only be able to conduct 20% of the resistive load rating. You may need a contactor with a much higher current rating to power your lights and fans if the sum total of current is past the inductive load rating of the timer. Regardless of the timers current rating it is always good to have the reliability of a high current rating contactor to supply inductive loads. Use the timer to energize the 120 volt holding coil of a Size 1 3-pole motor starter. The motor starter can directly supply three separate loads or a combination of loads not surpassing the current rating of each contact. If you need that set up , do some searching for motor starter diagrams.
Use every fan you have to exhaust heat. Redundancy is the key to reliability. To achieve full redundancy you will need to have a separate 12V power supply for each fan. If one power supply fails , you will have the other fans going. If you choose to use 1 power supply, don't load past 50 percent of the current rating. If something gets stuck in one of the fans or the fan is stuck for one reason or the other, the current will spike and you will lose all the fans. That could still happen even if you rate that single power supply accordingly. Better to have a separate power supply for each one. They're not expensive.
The effect of using lower voltage is that the lower the voltage gets the less wire you can use for connecting the equipment. Becomes more of a problem when you try to connect multiple fans to one power supply. More wire= more voltage drop=higher current=more of a chance of blowing the one time fuse encased in a molded low voltage power supply=more chances of losing all heat extraction if all the fans are connected to one power supply.
It definitely matters what voltage is the power supply. Match the voltage of the equipment, unless you want to fry it. There are only rare cases where resistive devices can be wired in series to accommodate higher voltage power supply. This is not one of those cases. Also, no intake fans needed. Simply make holes equal to 4x the square inch area of the exhaust outlets for intake holes. If the fans in question do not move the same amount of air as the max cfm rating of the most powerful centrifugal fans on the market with the same diameter as your fans, than you could probably have less square inch area for your intake holes.
P.S. 3 medium fans are not more efficient than 1 large fan, but it is a much more reliable configuration to have 3 fans instead of 1.
jabolo
Active Member
Hi and thanks a lot for your reply!
As it stands I don't understand half of what you wrote, but I'll start by googling all of it bit by bit until I get it, it's not your explanation the problem but rather my very poor grasp of electrics...
Bottom line:
1. I understand that I should use a contactor between my lights and my timer. Need to research on this as I have no idea what this is. But I understand that it is NOT safe to use my timer to plug in my lights (the fans will fun 24/7 - I don't think I'll plug them to the timer as I think the plant will need ventilation even when the lights are off).
If I'm using 3 26w bulbs, on a supply of 240v, it means my amp for each bulb is 26/240=1.smtg A? So 3 bulbs would be about 3A?
I'm prolly wrong on this: current = power / voltage?
2. I understand the bit about using 3 adaptors for 3 fans so that the ventilation is more reliable in case something goes pear shaped with one of the fans.
As for the fan voltage, I'm using only 12V charger(s) as you advised.
Thanks for the intake fan idea, just to be sure - if my exhaust area is a total of say 8 square inch, then I should use 8*4 = 32 square inch holes for passive intake?
Many thanks again for your help. I guess I gotta spend some time reading on all this...man how I wish I'd paid more attention in my physics class!
From looking around it seems that there're some pretty ghetto setups out there, but I'm really worried about something going wrong with the box and my room catching fire and exploding (weed induced paranoia or justified fear?) ...which is why I really want to understand all this electric setup before I start my 'project' even if it means delaying the whole thing....
J.
In a sub-panel the neutral wires are mounted on one bar that is mounted on plastic insulators so that it will not bond with the enclosure. This is refer to as "floating the neutral wires". This step alone has created only one pathway for neutral currents to travel to the main panel (we want only one pathway for neutral currents). Because current flowing through a wire create an impedance in that wire, this neutral pathway is also called a high impedance pathway. When a short circuit fault occurs between a hot wire and a enclosure, the fault current must have a separate low impedance pathway to the main panel in order for the circuit breaker to function quickly. The equipment grounding conductor provides this low impedance pathway. The equipment grounding conductor is connected on a separate bar in the sub-panel that is not insulated from the enclosure.
contraptionated
New Member
Hey Jabolo! I didn't know your lights would be such a low wattage. Don't worry about using a motor starter for a contactor. Just use some general purpose relays (4 pole is good for 2-240V lights) to supply the loads since they are relatively tiny. Buy yourself 4-4 pole 240V general purpose relays. Let the timer energize the coil of the relay and use the Normally Open contacts on either side of the relay base terminals to conduct the loads when the timer calls for it.
A general purpose relay contact is good for 1 amp inductive and your lights are only 26W @240 Volts so you're not even pulling 1/10th of an amp per light. You can get the relays (with the base included) for about 10 usd each (roundabout) on ebay. My favorite brand of relay is idec. Sometimes you can get them cheap at an electrical supply house that specializes in switchgear.
Check out elec-toolbox dot com for helpful wiring diagrams.
A general purpose relay contact is good for 1 amp inductive and your lights are only 26W @240 Volts so you're not even pulling 1/10th of an amp per light. You can get the relays (with the base included) for about 10 usd each (roundabout) on ebay. My favorite brand of relay is idec. Sometimes you can get them cheap at an electrical supply house that specializes in switchgear.
Check out elec-toolbox dot com for helpful wiring diagrams.
jabolo
Active Member
Thanks again mate! Yesterday was my first day w/out any green (spending my money on equipment rather than on my dealer lol) and I must admit reading your reply made me really worried about my setup!
I still don't understand all of what you've said, but you've mentionned some key words that'll help me do some more specific research!
Thanks!
J.
contraptionated
New Member
You are only half right. The neutral is indeed isolated, you would only refer to it as "floating" in slang. I like to keep my terminology uniform with the NEC, this way when somebody checks my advice with the only reference literature that matters, the lingo matches up. The grounding conductors (green wires) are also isolated (floated as you refer to it) from the panel enclosure in a sub panel. Ill say this again, but next time I will cite the appropriate section of Article 250 of the most recent edition of the NEC if that's what it takes.
It is obvious that you don't realize the code has changed in recent years in respect to grounding. The homeowner is forced to use a grounding conductor in all branch circuit wiring originating from a sub panel. The metal enclosures of equipment and device boxes get a grounding connection (bond) do that safety is there for human life as usual, but if you bond the grounding bar at the sub panel it's wrong.
Here's how debate works. You say to do something because of a belief. I strike down that belief by telling you it's not code. If you want to tell me otherwise, at least paraphrase the appropriate sub-section of the most recent NEC to prove your stance.
But at the very least, you need to use proper terminology. Repeat after me ...I-S-O-L-A-T-E-D.
What you're not understanding is that the sub-panel is like another device box. The original question from legallyflying was whether or not he had to bond the ground bar (neutral) or the grounding bar (green) to the sub panel enclosure. The answer is no for either of those "bars". But if you go back in the thread, Legallyflying said he would be using pvc conduit between the main panel and the lighting controller (sub panel). That is why I suggested a grounding conductor from the main panel to the lighting controller. The lighting controller enclosure gets a grounding conductor bonded to it like any other device box, originating from the grounding bar at the main panel. The lighting controller grounding bar gets a grounding wire connection from the main panel grounding bar , but no bond to the enclosure.
Now understand this. The code in your city may require more than the NEC. But in this case I know I cited the NEC and I don't think that local code varies much with sub-panel grounding.