Members ctardi Posted July 17, 2006 Members Share Posted July 17, 2006 That's what deep boxes are for. Actually, i'm not sure if you would be allowed to to a proper grounding scheme in a shallow box with 12 guage...i'll have to do some reading in all my 'spare time'. Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted July 17, 2006 CMS Author Share Posted July 17, 2006 Originally posted by milesdf this is exactly what i have done with about 15 quad boxes, lock nutted + locktited the receptacles to the faceplate, on both the ends where the copper grounding thingy springs against the faceplate. the ground goes to one of the receptacles. can anyone see this spontaneously failing? i mean maybe the screws could work themselves loose over time or something similar, but as long as im not dealing with quad boxes that arent falling apart its not just gonna go at a show.none of the ones ive ever built in my current place of work or my old job or for my house have never been up to code (for stage use) anyway, as they've all been SJ.in other words, im not too worried about code, just that it doesnt kill people.plus, its already very very hard to fit as much 12 guage wire into a quad box that i use now, adding all the ground connections might be impossible What you describe sounds problematic from the standpoint that it appears by your description that one receptacle is relying on having its ground provided via its connection to the box and further to the box's connection to the other receptacle. Note that only receptacles that have a grounding device on the mounting flange (looks like a bronze strap) should be used for grounding to a box, and I emphasize that this is only to provide the *box* with grounding via a grounded recep, not the other way 'round. This is dangerous after a given period of time, as the fastenings will corrode and can loosen...and if they're loc-tited, the compound compromises the connection. I use only wet location boxes...the cast metal ones...and they are a tight fit but are definitely to-code for box-fill...two receptacles and an entry cable are what they're made for. Link to comment Share on other sites More sharing options...
Members milesdf Posted July 17, 2006 Members Share Posted July 17, 2006 hmm, all the receptacles i have ever used have this "bronze strap", and in my mind i can't see this portion coroding before any of the other parts that would make me do some maintenence would. it is the little springy copper thing that sticks out from the bolting flange on (usally) the bottom of the receptacle right? as for the loctite, i don't think you understand the concept. the loctite is on the nut, there is no place where current would travel anywhere near it, especially because the purpose of the bolt is to hold the grounding strap against the box, not to facilitate ground through the bolt, but even if this were the case the current would still be traveling through only the bolt, no where near the loctite, right? also loctite is used as a dab on one side of the bolt, i would say covering a maximum of 25-50% of the connection between the nut and bolt, on a bolt that size. if the grounding flange is adequate to ground the box, why wouldn't it be safe to ground in the opposite direction? i guess in my application i have dependency on two connections vs. one if i was just grounding the box? im not trying to argue, im just trying to get sound theory on why I shouldn't trust the method that I was taught and have used for a while. in my mind and even expirience with my work and others, the one thing that fails in these items is the receptacle. hence the reason why I prefer SJ to SO. I can't really see or think of any reason why the extra expense or weight or pain is worth it. I've been with people that have used SJ forever and have never had any issues with the cable, even after using the same cable time and time again with many generations of boxes. it's just the boxes that get ratty and the receptacles that get broken. i've never seen a locknutted and loctited bolt fail, i've never seen (in the 10 or so quad boxes ive dissasembled due to failure/examination) any case where the (the method i use) ground path looks to have been compromised. I think in even the most code strict execution the thing that is going to kill is when you have something that doesn't look up to par, and you use it anyway. If something's coming loose, it needs to go in the repair pile. if you stick to that ethic, i don't see how my method for making these things is unsafe. not saying you can't convince me, its just that its gonna take more than a code argument. Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted July 17, 2006 CMS Author Share Posted July 17, 2006 Originally posted by milesdf hmm, all the receptacles i have ever used have this "bronze strap", and in my mind i can't see this portion coroding before any of the other parts that would make me do some maintenence would. it is the little springy copper thing that sticks out from the bolting flange on (usally) the bottom of the receptacle right? as for the loctite, i don't think you understand the concept. the loctite is on the nut, there is no place where current would travel anywhere near it, especially because the purpose of the bolt is to hold the grounding strap against the box, not to facilitate ground through the bolt, but even if this were the case the current would still be traveling through only the bolt, no where near the loctite, right? also loctite is used as a dab on one side of the bolt, i would say covering a maximum of 25-50% of the connection between the nut and bolt, on a bolt that size. if the grounding flange is adequate to ground the box, why wouldn't it be safe to ground in the opposite direction? i guess in my application i have dependency on two connections vs. one if i was just grounding the box? im not trying to argue, im just trying to get sound theory on why I shouldn't trust the method that I was taught and have used for a while. in my mind and even expirience with my work and others, the one thing that fails in these items is the receptacle. hence the reason why I prefer SJ to SO. I can't really see or think of any reason why the extra expense or weight or pain is worth it. I've been with people that have used SJ forever and have never had any issues with the cable, even after using the same cable time and time again with many generations of boxes. it's just the boxes that get ratty and the receptacles that get broken. i've never seen a locknutted and loctited bolt fail, i've never seen (in the 10 or so quad boxes ive dissasembled due to failure/examination) any case where the (the method i use) ground path looks to have been compromised. I think in even the most code strict execution the thing that is going to kill is when you have something that doesn't look up to par, and you use it anyway. If something's coming loose, it needs to go in the repair pile. if you stick to that ethic, i don't see how my method for making these things is unsafe. not saying you can't convince me, its just that its gonna take more than a code argument. All of this is well and good, I'm not arguing it either. I'm speaking strictly from the aspect of Code compliance and the reasoning behind it (or my understanding of the reasoning). A green bolt properly tightened over the actual grounding conductor is a known good method, and fewer connections, especially those that are doing something else like holding the receptacle to the box, are better. Fwiw the little bronze-likle strap is by no means a univerallly present device on receps. I understand your explanation of the loctite-nut-bolt setup, but I was describing two separate parts...the bolt/nut with loctite won't readily pass current, and the mating of the strap/clip/box is prone to corrosion depending upon envoronment. This is why Code is reluctant to approve this as a means of grounding the box. And I'll stress that grounding the second recep via the box connection is scary. Anything plugged in downstream is dependent on that path to ground. I wouldn't feel comfy touching an amp case plugged into that on a rainy day outdoor festival..... Link to comment Share on other sites More sharing options...
Members milesdf Posted July 17, 2006 Members Share Posted July 17, 2006 Originally posted by Craigv And I'll stress that grounding the second recep via the box connection is scary. Anything plugged in downstream is dependent on that path to ground. I wouldn't feel comfy touching an amp case plugged into that on a rainy day outdoor festival..... very good point. but i wouldn't think that the plate is any less of a conductor than a direct wire path, or at least not by too much. but your right a fire could result. some testing may be in order. Link to comment Share on other sites More sharing options...
Members rxnet Posted July 17, 2006 Author Members Share Posted July 17, 2006 I knew this was headed to code.......... Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted July 17, 2006 CMS Author Share Posted July 17, 2006 Originally posted by milesdf very good point.but i wouldn't think that the plate is any less of a conductor than a direct wire path, or at least not by too much. but your right a fire could result. some testing may be in order. It is less conductive...it's not a copper path, and every connection point loses conductivity. But the issue isn't when the setup is new...it's after it's aged and been rained on and sat in humid trunks and through miles of road vibration. The fact that you'll have dissimilar metals at each of the multiple points makes it worse. It's not a big deal to correct. I run one wire from one recep ground, loop it around the other recep and then wirenut it to the box ground tail and the source ground. It's the only wirenut needed in the box and you can also get the green nuts with a tail built in to save a bit of time. Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted July 17, 2006 CMS Author Share Posted July 17, 2006 Originally posted by rxnet I knew this was headed to code.......... That's okay....keep it going long enough, and eventually a fight will break out over Behringer/Carvin/where02910...... Link to comment Share on other sites More sharing options...
Members agedhorse Posted July 17, 2006 Members Share Posted July 17, 2006 The screw with locknut connection is an acceptable grounding connection for a 20 amp circuit. The screw into the receptacle is not as good, which is why code wants to see a hard-connected bond. The single screw is ok for bonding the faceplate but there are no looped through connections on a stainless flush mount cover. Link to comment Share on other sites More sharing options...
Members milesdf Posted July 17, 2006 Members Share Posted July 17, 2006 Originally posted by agedhorse The screw with locknut connection is an acceptable grounding connection for a 20 amp circuit. The screw into the receptacle is not as good, which is why code wants to see a hard-connected bond. The single screw is ok for bonding the faceplate but there are no looped through connections on a stainless flush mount cover. wait, so can you clarify that my method is acceptable or not. what is a looped through connection? Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted July 17, 2006 CMS Author Share Posted July 17, 2006 Originally posted by agedhorse The screw with locknut connection is an acceptable grounding connection for a 20 amp circuit. The screw into the receptacle is not as good, which is why code wants to see a hard-connected bond. The single screw is ok for bonding the faceplate but there are no looped through connections on a stainless flush mount cover. Originally posted by milesdf wait, so can you clarify that my method is acceptable or not. what is a looped through connection? Andy, have a look at the new (2005) wording of 250.146 (A) and (B) as part of (A) through (D). Then see 250.148 especially 250.148(B). What I interpret; There's no specific amperage mentioned, so the articles aply to 15 and 20 amp circuits equally. While 250.146(A) appears to allow the receptacle yoke to ground the receptacle to a surface mounted box, 250.148(B) would absolutely disallow milesdf's method. He's using the box as a source of grounding, but he doesn't connect the incoming grounding conductor to the box. He connects it to one receptacle and depends upon that recep's yoke connection to the box for the other receptacle's grounding. Removing the receptacle that has the ground wire connection interrupts the box and the other recep's grounding. For the rest of us who don't have the Code book (it's boring and expensive anyway) one article states that it's okay to use receptacles that are UL-listed as self-grounding "Contact Devices" to use their yokes as ground to the box. The other article states that the grounding connections must be arranged so that removal of one device (receptacle in this instance) does not interrupt grounding continuity. milesdf, it appears that if you were to change the grounding conductor to bond to the box, and then use Listed self grounding receptacles that mount to the box (not to the cover, which then further requires that both the cover and the box are listed as providing satisfactory ground). Link to comment Share on other sites More sharing options...
Members agedhorse Posted July 17, 2006 Members Share Posted July 17, 2006 And this is exactly why I mentioned the gray areas. In operation, everything is solidly mounted and the grounds are continuous BUT if somebody removes a receptacle then differentthings can happen depending on the wiring methods. In a hard-pipe installation, the ground is carried throught the conudit system right through the box so there's no issue and I have seen installations with and without jumpers (of course both using metal boxes) pass inspection. Where things get muddy is using metal boxes with portable cord or Romex, as the grounding path must be deliberately made, and I generally prefer it made to the box (with pigtails to the yokes if plastic covers) as self grounding yokes work with this method and it's generally faster. Plastic boxes (of course) don't work this way though, and the ground must terminate directrly on the device yoke. Link to comment Share on other sites More sharing options...
Members rxnet Posted July 18, 2006 Author Members Share Posted July 18, 2006 I just knew it would come to this...Ijust knew it Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted July 18, 2006 CMS Author Share Posted July 18, 2006 Originally posted by rxnet I just knew it would come to this...Ijust knew it What, knowledge dissemination??? Shame, I know...... :D Link to comment Share on other sites More sharing options...
Members agedhorse Posted July 18, 2006 Members Share Posted July 18, 2006 Also, 15 and 20 amp branch circuits receptacles are considered the same, but 30 amp and higher are considered "heavy duty" and have some different code issues as do the heavy duty lamp holders. Link to comment Share on other sites More sharing options...
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