[rasputin]

Awesome information here! To all who've shared, this is a tremendous resource. Many thanks!

[madpenguin]

You basically want to create a low impedance dedicated return path for any ground fault current if it occurs. The neutral wire of the feeder going back to the main panel should only carry the return current at all times, just as a 14/2 branch circuit neutral should only carry the return current at all times.

There should only be one point where neutral and ground are bonded together and that's typically in your main panel, or rather, at your main service disconnect (which can sometimes be outside in a separate enclosure).

On a semi related note, in most houses you have the meter outside and the main panel in the basement practically 5 feet away from the meter. The incoming SEU cable is unfused so it has to go directly into your main panel with the service disconnect, otherwise it's a potential fire hazard. If the SEU cable had to travel more than 5 feet or so inside your house, you need to have your main service disconnect outside, and then use SER from the disconnect to your "main panel". Then you would need to attach the ground rod and water meter bond to the outside disconnect instead of your panel (they would attach to the neutral in the outside disconnect).

There are many different requirements if your installing a sub-panel in a detached structure (garage, shed, barn). The above post was for a sub-panel in the same house as the main panel.

[madpenguin]

Originally Posted by mikecar312

can you explain why neutrals and ground are ok at the main panel but not ok in the sub panel? i know it has something to do with the ground being uninsulated so it shouldn't be connected to the same bus as the neutral which carries a charge. what can happen if this is done...just an electric shock every once in a while?

Sorry. Don't think I actually answered the question. In that instance, you would provide a parallel path for neutral current to travel on. Some would take the neutral and some would take the ground.

Also why you don't want to terminate any neutral wires to the dedicated ground basbar in a sub-panel. You would have objectionable current on the frame of the panel. If you didn't use the bonding bar/strap/screw, then you force the neutral current to travel down the grounding conductor. If you did use the bonding bar/strap/screw, then your back to having parallel paths, along with objectionable current on the frame of the panel.

[madpenguin]

Just know that current always wants to get back to it's source, which is the center tap at the transformer. It doesn't care how it gets there, just that it does.

I was working at someones house and the bonding jumper to the water meter shocked the shit out me. It read constant voltage. Threw her main disconnect and it still read voltage.

That's when I call the Power Company. It turned out that the next door neighbor had a loose neutral at their disconnect. All the current they were using had no where to go (back to the transformer on the pole), so it traveled down their bonding jumper to their water meter, out thru their front lawn on the water pipe, down the street about 20 feet, and back up thru this lady's house to her water meter, across her bonding jumper and then out her neutral to the transformer. This is why you absolutely do not switch neutrals. You'll still find switched and fused neutrals in old houses with Knob & Tube wiring.

So.... It always want's to go back to the source and doesn't care what path it takes (including you). When you wire, you need to force it to take the most safest route and least resistive route.

Originally Posted by madpenguin

Yea, I realize you can't have an electrician come in while the op. is in progress... With proper planning, all the wiring should be done before hand. Even then, upgrades are sometimes necessary. So this is why we do it ourselves.

I have no problem with standard wiring procedures being done by homeowners. It's really quite easy once you get the basics down. It's when you start dealing with motor controls, ballasts et. all that a "qualified" person should be doing the work. Again, just make sure you know what your doing beforehand.

ACtually it IS the more complicated stuff that we cant outsource. I used Sunsystem ballasts with Hydrofarm hoods. Who am I going to call to cut the plugs off and hardwire them? Nobody, I had to do it myself. If a ballast goes bad, who am I going to have fix it? Nobody, myself.

And if setting up a 5000+ grow, you cant really have an electrician in. There is no reasonable reson for wanting so much power, in such a small space with outlets everywhere you need it.

It would be nice if we had a dedicated electrical section where anyone could post topics, but only a qualified few could respond.


The info posted here is very helpful

[nephilthim]

Originally Posted by madpenguin

And since we are now on the subject, I might as well throw this out in the open before the thread progresses too much farther.

If anyone has any doubts as to how to wire something correctly, then just don't do it.

I have a real problem with some folks around here giving advice as to dismantling ballasts, transformers, variacs and the like. I don't mean to belittle anyone on this forum, but that is way beyond the ability of the average person. I realize a lot of you are technically inclined and can do such things but to give such advice and word it like it's no big deal is morally and ethically wrong. I will not be responsible for the death of any member here so I will never tell someone how to do such things. My answer will, and always will be, "return it". And on a much lesser note, you void your warranty when you do stuff like that. You paid good money for your equipment so just return the damn thing. You shouldn't be expected, as a consumer, to have to service your own electrical equipment.

In fact, I should probably quit posting electrical related topics all together. Electricity is nothing to take lightly. People under estimate residential voltage all the time. The current that a 60w light bulb draws will kill you in a heart beat. Period. If the path crosses your heart, kiss your ass goodbye. Even if it doesn't cross your heart, but you manage to get "hung up", kiss your ass goodbye.

Also, you guys should understand my frame of mind. Yes, I'm an electrician. I love my job. I don't do it for the money. I do it because I thoroughly enjoy working with electricity. I'm an anal son-of-a-bitch and I take longer to do something than your average electrical contractor. Why? Because I do things the right way, not the quick way. If your really good, you can balance both (which I have a hard time doing). Thus, I no longer sub anymore but just work for a company.

So, being the way that I am, The National Electrical Code is scripture to me. Every article in the NEC was put there because someone died. Back in the early 1900's it was a very thin book. Look at how big it is now. So, actually, me telling anyone "unqualified" (yes, it's defined in the NEC) to do work without a permit is morally and ethically wrong. The shit needs to be inspected. If you own your own home, many jurisdictions will allow the home owner to pull a permit. If you live in an apartment, you really should not be doing the work yourself. You make a mistake and you kill everyone in the building. Could you live with yourself if you made a mistake wiring your grow room and your next door neighbors 4 year old daughter burned alive in her bed? Not me.

Or get this.... Say member "kindbud69" received some advice here to swap out the capacitor on his 1000w ballast. "O.K... Sounds easy enough". So kindbud69 goes down in the basement to his grow room to get the ballast. Since he enjoys being in his grow room, he gets a chair and a collapsible TV dinner table and decides to do the work there. Chillin with the plants on a lazy Sunday afternoon, gonna fix my ballast, life is good. Set's the ballast on the table. Takes the housing off. Correctly identifies the capacitor and starts to remove it.

BAM

Kindbud69 is now laying on the floor in cardiac arrest. Too bad joeschmoe589 forgot to mention that the capacitor could very well be charged still. Even more of a shame that kindbud69 had a small hole in his left shoe sole. Worse yet, kindbud69 spilled some water when topping off his res an hour earlier and happened to have his left foot sitting on a wet and grounded surface (concrete floor).

Too bad joeschmoe589 will never know that he indirectly just killed someone. Look at the last line in my sig and ignore the smiley face. It's probably the best thing you can do if you have any hesitation as to how to do something.

Sorry for the book but I take it very seriously and you guys should to. Also, if it's not obvious yet, any and all advice that I give is based upon 120/240v 60hz American electrical systems. If you live in Europe or anywhere else (most of the world) that deals with different voltages or frequencies, then you probably shouldn't be listening to me.

I have no prob I try to help people with what little I know about changing cords on a ballast,voltage drop,problems,and if anyone is uncomfortable.don't mess with it and get an electrician
I have been shocked with 110 I have seen a friend after he was zapped with 277 glad it wasn't 480.electricity is something definitely to be anal about if you want to live long.just like you shouldn't disable or put awater heater without a t.m.p. valve.
I have taking a lot of code related subjects ,plumbing,concrete,building,fo r all of you old far electricians hands hurting frrom fucking with wire.you need,no should get your inspection certification,and anything else you can cert yourself.concrete,pulmbing,bui lding code,mechanical,hvac.
thelatest one coming down the pipe is A.D.A. all new buildings will in the future require an inspection certification for compliance with all provisions of this act as it relate to buildings.
lastly I figure if someone wants to fuck with electricty without seeking consultation checking,backchecking or waiting to hear from you certified guys
if its right wrong.then they are a canidate for a darwin award.
and don't feel to bad people die all the time,and the world has enough so feel good if you contribute to population control.

[packn2puff]

Just to let you all know..this is now considered a code violation by the NEC..
Neutral connections need to be pigtail spliced these days(like the green ground is shown)..not made at the yoke of the receptacle or device..
Was a common practice back-in-the-day..

Sorry didn't read the whole thread..but I'll also share that ampacity is related to wire insulation..the chart provided is for 90C rated wire like THHN..
Fortunately most insulation these days is THHN..for other insulation types and ambient temps it's used in see National Electrical Code table 310.16

"But packn I don't have a code book"..well my friends there is a very helpful little book at Hemp Depot..ahhh Home Depot..in the electrical dept..
called the Ugly's book..has common charts and other fun electrical stuff..

ps..they call it 2-wire even though you see 3 physical wires..Ground isn't counted..ie above pic is probably sold as Romex 14/2 with ground

All for now..me..licenced electrician

[madpenguin]

Originally Posted by packn2puff

Just to let you all know..this is now considered a code violation by the NEC..
Neutral connections need to be pigtail spliced these days(like the green ground is shown)..not made at the yoke of the receptacle or device..

Huh? Have an Art. number handy? Always a good idea on MWBC's but there is no requirement that I'm aware of for 120v 2 wire loads. If you want to be anal to make sure no open neutrals happen then it's a good idea, but not required, even on Multi Wire Branch Circuits.

Originally Posted by packn2puff

Sorry didn't read the whole thread..but I'll also share that ampacity is related to wire insulation..the chart provided is for 90C rated wire like THHN..
Fortunately most insulation these days is THHN..for other insulation types and ambient temps it's used in see National Electrical Code table 310.16

Right. But the ampacity for romex is still based upon 60 Celsius, however, your allowed to start de-rating at 90 because of the THHN conductors.

Ugly's is a great book to have... Also, Lowes and Home Depot have alot of other general electrical books that are good for learning the basics of home wiring.

[packn2puff]

Originally Posted by madpenguin

Huh? Have an Art. number handy? Always a good idea on MWBC's but there is no requirement that I'm aware of for 120v 2 wire loads. If you want to be anal to make sure no open neutrals happen then it's a good idea, but not required, even on Multi Wire Branch Circuits.

NEC Art 300..300.13(b)
In multiwire branch circuits, the continuity of a grounded conductor shall not depend on device connections
such as lampholders, receptacles, and so forth, where the removal of such devices would interrupt the continuity.

This has been in there since at least the 2005 code book..

Right. But the ampacity for romex is still based upon 60 Celsius, however, your allowed to start de-rating at 90 because of the THHN conductors.

Did not dispute this..all ampacity derating calculations is done using 90C, provided the final calc does not exceed ampacity of 60C rated conductor..334.80

Sorry I tried to help a little..not trying to stir things up..but I do this for a living..mostly commercial & industrial..sometimes residential

[madpenguin]

Originally Posted by packn2puff

NEC Art 300..300.13(b)
In multiwire branch circuits, the continuity of a grounded conductor shall not depend on device connections
such as lampholders, receptacles, and so forth, where the removal of such devices would interrupt the continuity.

This has been in there since at least the 2005 code book..

Right. MWBC's. The pic shown isn't a MWBC so is ok. Thanks for the Art. Wasn't actually aware it was required but always do it anyway so the loads don't become in series with one another if a loose neutral occurs. It makes sense that the NEC would state it.

Did not dispute this..all ampacity derating calculations is done using 90C, provided the final calc does not exceed ampacity of 60C rated conductor..334.80

Sorry I tried to help a little..not trying to stir things up..but I do this for a living..mostly commercial & industrial..sometimes residential

Right. I knew what you meant. Was just clarifying so people don't start putting 30A breakers on #12 romex is all. You wern't stiring things up and it was a great post. It seems evident that I should more carefully phrase some of my replies. I encourage anyone to post here. More often than I'd like, I state completely false shit and it would be nice if you guys caught me on it...