ProSoundWeb Community

Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Sean Proken on May 27, 2014, 09:11:49 pm

Title: Feeder Cable length?
Post by: Sean Proken on May 27, 2014, 09:11:49 pm
Hi!

I use a 50amp distro in my system, and recently picked up a gig where the only available outlet is about 200' away. Ive never done a run this long, and I only own one 50' 6/4 cable, so I would like to know if the length is an issue before I invest in more cable.


Thanks.
Title: Re: Feeder Cable length?
Post by: g'bye, Dick Rees on May 27, 2014, 09:21:42 pm
Hi!

I use a 50amp distro in my system, and recently picked up a gig where the only available outlet is about 200' away. Ive never done a run this long, and I only own one 50' 6/4 cable, so I would like to know if the length is an issue before I invest in more cable.


Thanks.

Get a generator and site it so you can use the cable you own.  200' run requires 4 gauge wire.  That's a s***load of copper, heavy and expensive...and a really looooong tripping hazard.
Title: Re: Feeder Cable length?
Post by: Rob Spence on May 27, 2014, 09:29:01 pm
Hi!

I use a 50amp distro in my system, and recently picked up a gig where the only available outlet is about 200' away. Ive never done a run this long, and I only own one 50' 6/4 cable, so I would like to know if the length is an issue before I invest in more cable.


Thanks.

How much current do you draw?

I have run 200' from a genny with 100' of 6/4 and 100' of 6/3+8/1 (supplied with genny).
I was only running 4 QRX 212, a couple of front fills and a couple of wedges. No lights.
I have also run 150' with the above and 4 subs.

That said, if I were buying another 100' of feeder I would make it 4/4 or to reduce weight & size, 4/3+6/1.



Sent from my iPad using Tapatalk HD
Title: Re: Feeder Cable length?
Post by: Sean Proken on May 27, 2014, 09:32:55 pm
How much current do you draw?

I have run 200' from a genny with 100' of 6/4 and 100' of 6/3+8/1 (supplied with genny).
I was only running 4 QRX 212, a couple of front fills and a couple of wedges. No lights.
I have also run 150' with the above and 4 subs.

That said, if I were buying another 100' of feeder I would make it 4/4 or to reduce weight & size, 4/3+6/1.



Sent from my iPad using Tapatalk HD

I run it at almost full load. 4/4 is really expensive, guess i'll just make my client rent a generator or pass on the gig.

Thanks for the info guys.
Title: Re: Feeder Cable length?
Post by: TJ (Tom) Cornish on May 27, 2014, 09:37:39 pm
I run it at almost full load.
How do you know?
4/4 is really expensive, guess i'll just make my client rent a generator or pass on the gig.

Thanks for the info guys.
At 200', even 4/4 could get a little small if you're truly running close to 50A a leg, which isn't difficult with amplifiers where instantaneous current can be pretty significant.  A generator is the right call here, or possibly renting some larger feeder.
Title: Re: Feeder Cable length?
Post by: Mike Sokol on May 27, 2014, 11:18:56 pm
How do you know?At 200', even 4/4 could get a little small if you're truly running close to 50A a leg, which isn't difficult with amplifiers where instantaneous current can be pretty significant.  A generator is the right call here, or possibly renting some larger feeder.

+1
Title: Re: Feeder Cable length?
Post by: Sean Proken on May 27, 2014, 11:26:11 pm
How much current do you draw?

I have run 200' from a genny with 100' of 6/4 and 100' of 6/3+8/1 (supplied with genny).
I was only running 4 QRX 212, a couple of front fills and a couple of wedges. No lights.
I have also run 150' with the above and 4 subs.

That said, if I were buying another 100' of feeder I would make it 4/4 or to reduce weight & size, 4/3+6/1.



Sent from my iPad using Tapatalk HD

About a year ago I did a gig where the venue only had a 14-30 outlet. it was last min with no time to request a new outlet install, so we made an adapter. The breaker was blowing all night, to the point I could not turn the sound up loud enough. Now I run 4 moving heads and some wash lights as well, so I have to be pretty close to a full 50amp load.


Generator it is. What size do you recommend? 35kva?
Title: Re: Feeder Cable length?
Post by: Ray Aberle on May 28, 2014, 12:03:20 am
About a year ago I did a gig where the venue only had a 14-30 outlet. it was last min with no time to request a new outlet install, so we made an adapter. The breaker was blowing all night, to the point I could not turn the sound up loud enough. Now I run 4 moving heads and some wash lights as well, so I have to be pretty close to a full 50amp load.

Generator it is. What size do you recommend? 35kva?

The bad part about that adapter is what you discovered: By having a 30A breaker "somewhere else" other then your distro, you pop that breaker before something local (read: easy to reset) would trip out. Awkward. :(

Generator is your friend. A 25kW will have it's two CS6369 50A flush mount receptacles on a 60A/220 main breaker (at least with a Multiquip WhisperWatt). So, that should give you enough without causing any problems. The next step up is the 45kW (which is what I have) - the main breaker is 110A/220V. You can also go 3(camlock) to a distro with a couple of range plugs on it-- that would give you the full capacity of the generator available.

Easiest (what most generator rental houses have) is to use the twistlocks, though. :) You didn't mention what your distro's input style is, so make sure you can get to the CS 6369 ("california connector") OK.

-Ray
Title: Re: Feeder Cable length?
Post by: Jeff Bankston on May 28, 2014, 06:09:52 am
you could run 2 paralell extension cords into a 2 in 1 out box. the cords need to be the same lenght. you might have to build the box. 2 male plugs in and 1 female out. on the power in side you would need to plug both cords into the outlet and it would need to be in a place that no one but you will have access to lest someone unplugs a cord and has hot prongs proding them. if your not familiar with this then dont do it. i'm an electrician and it no big thing for me. 2 , 3 and 4 hot wires on the same phase is very common. i have pulled Four paralell runs of 750mcm quit a few times. i also pulled a 1000mcm once and that was enough. all copper.
Title: Re: Feeder Cable length?
Post by: David Sturzenbecher on May 28, 2014, 08:29:11 am

you could run 2 paralell extension cords into a 2 in 1 out box. the cords need to be the same lenght. you might have to build the box. 2 male plugs in and 1 female out. on the power in side you would need to plug both cords into the outlet and it would need to be in a place that no one but you will have access to lest someone unplugs a cord and has hot prongs proding them. if your not familiar with this then dont do it. i'm an electrician and it no big thing for me. 2 , 3 and 4 hot wires on the same phase is very common. i have pulled Four paralell runs of 750mcm quit a few times. i also pulled a 1000mcm once and that was enough. all copper.

Is that acceptable by code? I have never seen it done on high voltage before... Speaker lines sure..


Sent from my iPhone using Tapatalk
Title: Re: Feeder Cable length?
Post by: Tim McCulloch on May 28, 2014, 10:05:00 am
Is that acceptable by code? I have never seen it done on high voltage before... Speaker lines sure..


Sent from my iPhone using Tapatalk

It's allowed for single conductor feeders, same length, etc.  Not sure about doing so with multi-conductor cables...
Title: Re: Feeder Cable length?
Post by: Kevin Graf on May 28, 2014, 01:25:40 pm
In most cases the NEC only permits 1/0AWG and larger wires to be paralleled.
Title: Re: Feeder Cable length?
Post by: Jeff Bankston on May 28, 2014, 05:05:41 pm
Is that acceptable by code? I have never seen it done on high voltage before... Speaker lines sure..


Sent from my iPhone using Tapatalk
i'v never seen where it not. its no different from running multiple leg runs of 4/0 from a generator to a distribution panel like at concerts and movie sets.
Title: Re: Feeder Cable length?
Post by: Stephen Swaffer on May 28, 2014, 11:48:19 pm
NEC 310.10(H)(1) Limits paralleled conductors to 1/0 AWG and larger.  There are some exceptions but generally anything smaller is required to be protected at the ampacity of each individual conductor-mainly intended to allow redundant control conductors for reliability not extra current capacity.

Guess I wouldn't be comfortable with 2 male plugs paralleled together myself-can't seem to get away from Murphy's law in my neck of the woods!

Also, with tripping the 30 amp breaker.  You may well have been running over 30 amps, but I have seen many cases where a loose wire on the breaker will create enough heat (most breakers are both thermal and magnetic sensitive) to cause it to trip at a much lower current-same can happen with fuses.
Title: Re: Feeder Cable length?
Post by: David Sturzenbecher on May 28, 2014, 11:53:58 pm

NEC 310.10(H)(1) Limits paralleled conductors to 1/0 AWG and larger.  There are some exceptions but generally anything smaller is required to be protected at the ampacity of each individual conductor-mainly intended to allow redundant control conductors for reliability not extra current capacity.

Guess I wouldn't be comfortable with 2 male plugs paralleled together myself-can't seem to get away from Murphy's law in my neck of the woods!



This is why this is a bad and code breaking idea!! If your combiner is connected at the far end, plugging one male end into the outlet energizes the exposed prongs on the second male end.


Sent from my iPhone using Tapatalk
Title: Re: Feeder Cable length?
Post by: Jeff Bankston on May 29, 2014, 01:48:45 am
yeah but you are refering to extension cords and not a permanent installation. that why nec cannot regulate what people do with an extesion cord in side or outside. in cali only osha can regulate temp power cords on a job site. i can use the same spider box in my house and osha cannot come in and write me a fine up. what i suggested is not for just anyone and if i absolutely need a larger cord i would buy the larger cord.
Title: Re: Feeder Cable length?
Post by: Stephen Swaffer on May 29, 2014, 07:28:05 am
The OP was asking about an extension feeder in a public venue where he has both a legal and ethical responsibility to provide a safe environment.  IMO in these situations OSHA, NIOSH and the NEC are a starting point. 

My former employer often required going above and beyond to insure safety.  When the public (I viewed production employees as 'public') is involved the mindset can't be "Can this be done safely by a reasonable person?" as much as, "Is there any way an careless person can get hurt here?"  People can be seriously creative when it comes to finding ways to get hurt-no sense in making it easy for them.
Title: Re: Feeder Cable length?
Post by: Michael Ardai, N1IST on May 31, 2014, 08:47:06 pm
NEC 406.7 prohibits male plugs with energized prongs.  So it is a code violation as well as a potentially lethal safety issue.
/mike
Title: Re: Feeder Cable length?
Post by: James Cotton on June 04, 2014, 04:35:01 pm
you could run 2 paralell extension cords into a 2 in 1 out box.

In the UK that kinda thing is commonly known as a "widow maker". I'd have thought in the US you'd never even contemplate such a cable for fear of lawyers, never mind that it might kill someone who comes along looking for an outlet to plug the coffee pot into and cares little for what that plug may be powering.
Title: Re: Feeder Cable length?
Post by: TJ (Tom) Cornish on June 04, 2014, 04:50:02 pm
In the UK that kinda thing is commonly known as a "widow maker". I'd have thought in the US you'd never even contemplate such a cable for fear of lawyers, never mind that it might kill someone who comes along looking for an outlet to plug the coffee pot into and cares little for what that plug may be powering.
It's equally unsafe/illegal/idiotic here. 
Title: Re: Feeder Cable length?
Post by: Jeff Bankston on June 04, 2014, 07:19:00 pm
In the UK that kinda thing is commonly known as a "widow maker". I'd have thought in the US you'd never even contemplate such a cable for fear of lawyers, never mind that it might kill someone who comes along looking for an outlet to plug the coffee pot into and cares little for what that plug may be powering.
fisrt of all IF i ever had to use it it would be plugged into an off limits outlet with signs and tape and stuff and in plain view. secondly IF YOU allow someone to unplug your board or other gear then you are not making sure you have made it known to whoever that the outlet your plugged into is off limits. and anyone pulling a plug before asking needs their rear reamed out real good. i have never encounterd anyone wanting to pull a plug witout asking if its being used.
Title: Re: Feeder Cable length?
Post by: Tim McCulloch on June 04, 2014, 07:28:24 pm
fisrt of all IF i ever had to use it it would be plugged into an off limits outlet with signs and tape and stuff and in plain view. secondly IF YOU allow someone to unplug your board or other gear then you are not making sure you have made it known to whoever that the outlet your plugged into is off limits. and anyone pulling a plug before asking needs their rear reamed out real good. i have never encounterd anyone wanting to pull a plug witout asking if its being used.

Stupid or selfish people will do the darndist things, Jeff.  Mac Kerr posted about losing a Red Carpet video feed because a "guest" unplugged the fiber optic converter PSU to plug in his/her cellphone charger.
Title: Re: Feeder Cable length?
Post by: Tom Bourke on June 04, 2014, 08:04:28 pm
fisrt of all IF i ever had to use it it would be plugged into an off limits outlet with signs and tape and stuff and in plain view. secondly IF YOU allow someone to unplug your board or other gear then you are not making sure you have made it known to whoever that the outlet your plugged into is off limits. and anyone pulling a plug before asking needs their rear reamed out real good. i have never encounterd anyone wanting to pull a plug witout asking if its being used.
Stop digging your hole.  It's a bad idea and very dangerous.
Title: Re: Feeder Cable length?
Post by: Jeff Bankston on June 04, 2014, 09:53:08 pm
Stop digging your hole.  It's a bad idea and very dangerous.
if you ever worked on a construction job, did service work on some of breaker panels that non electricians used to turn building lights on with and replaced some of the (wth is this) recepticales i have you would understand that what i'm refering to would not even make it close to the dangerous list. i have seen and ben around some unbelievalbly dangerous installed equipment that watresses plugged vacuums in and out of. let me put it this way, theres stuff i have ben called to repair and work on that i didnt even want to get near untill the power was turned off to the switches , plugs or main service that others were within inches of.
Title: Re: Feeder Cable length?
Post by: TJ (Tom) Cornish on June 04, 2014, 10:49:53 pm
if you ever worked on a construction job, did service work on some of breaker panels that non electricians used to turn building lights on with and replaced some of the (wth is this) recepticales i have you would understand that what i'm refering to would not even make it close to the dangerous list. i have seen and ben around some unbelievalbly dangerous installed equipment that watresses plugged vacuums in and out of. let me put it this way, theres stuff i have ben called to repair and work on that i didnt even want to get near untill the power was turned off to the switches , plugs or main service that others were within inches of.
So...you're saying that because there is other really scary stuff out there, it's ok to promote stuff that is only kind of scary, but still illegal and dangerous (and quite frankly unnecessary)? How about we suggest actual code-compliant, workable solutions instead?
Title: Re: Feeder Cable length?
Post by: Tom Bourke on June 04, 2014, 11:47:12 pm
if you ever worked on a construction job, did service work on some of breaker panels that non electricians used to turn building lights on with and replaced some of the (wth is this) recepticales i have you would understand that what i'm refering to would not even make it close to the dangerous list. i have seen and ben around some unbelievalbly dangerous installed equipment that watresses plugged vacuums in and out of. let me put it this way, theres stuff i have ben called to repair and work on that i didnt even want to get near untill the power was turned off to the switches , plugs or main service that others were within inches of.
That almost makes it worse.  Since it does not look scary to the untrained eye some one may assume it is safe to touch.   
Title: Re: Feeder Cable length?
Post by: Mike Sokol on June 05, 2014, 07:25:02 am
That almost makes it worse.  Since it does not look scary to the untrained eye some one may assume it is safe to touch.

Let's stay OT. This forum will only promote solutions that are NEC and UL compliant. The only exception will be if we feel that the Code itself is incorrect and we're going through proper channels to modify the code. (I'm doing that right now)

Also remember that this is a learning forum. So if someone makes a suggestion that's dangerous or a code violation, we need to point it out without attacking the individual. And if you find that you've been wrong about something, then admit it and move on. I myself have done some cringe worthy things over the last 40 years, which I'll be glad to discuss as fails. And certainly, there's often pressure to cut safety corners at gigs since "the show must go on". But that attitude has contributed to stage collapses in storms and fires from pyro gone wrong. And yes, equipment damages and injuries or death from incorrect electrical hookups happen all the time.

So NO personal attacks and retaliation here. In this classroom we're all free to ask questions without being judged. Let's stay safe out there.

Professor Mike Sokol (Yes, I really am an adjunct professor at Shenandoah University)
   
Title: Re: Feeder Cable length?
Post by: Jeff Bankston on June 07, 2014, 12:32:19 am
So...you're saying that because there is other really scary stuff out there, it's ok to promote stuff that is only kind of scary, but still illegal and dangerous (and quite frankly unnecessary)?
i did not say that and was not implying that either.
Title: Re: Feeder Cable length?
Post by: Jeff Bankston on June 07, 2014, 12:34:30 am
That almost makes it worse.  Since it does not look scary to the untrained eye some one may assume it is safe to touch.
you would be surprised what i'v seen on job sites when the general contractor was responsible for all the temp power. and nobody on any of the trades cared as long as their power tools worked. thats why construction is in the top 10 dangerous jobs. i have called osha and reported dangerous conditions on a number of jobs after the superintendant wouldnt do anything. osha came out once and it wasnt for the temp power issue i called about. i was more concerned about some of the apartment buildings i lived in when i saw people with tv, stereo , floor lamp, etc plugged into a 16 gauge zip type extension cord.
Title: Re: Feeder Cable length?
Post by: Ray Aberle on June 08, 2014, 02:47:43 pm
i did not say that and was not implying that either.

Per Mr. Sokol, we need to stay on topic, and NOT promote/suggest, or even mention-as-an-option any kind of solution that would be in violation of the applicable NEC and OSHA regulations. The box that led to this topic swerve, your "widow maker" with (details redacted as to not mention it again) is dangerous, illegal, and in violation of the NEC.

Mr. Cornish said what he said because you tried to defend your mentioning of this custom box with "there is way more scary stuff out there then what I mentioned," - just because there's other reprehensible violations of both the NEC and OSHA regulations, as well as good, common sense existing on construction/other sites, you still may not recommend a "not so dangerous but still illegal device" on these forums.

We need to be leaders in the entertainment field, making sure that we are doing everything we can to promote safe and responsible electrical practices!

Thanks--

Ray
Title: Re: Feeder Cable length?
Post by: Jeff Bankston on June 09, 2014, 11:16:24 pm
Per Mr. Sokol, we need to stay on topic, and NOT promote/suggest, or even mention-as-an-option any kind of solution that would be in violation of the applicable NEC and OSHA regulations. The box that led to this topic swerve, your "widow maker" with (details redacted as to not mention it again) is dangerous, illegal, and in violation of the NEC.

Mr. Cornish said what he said because you tried to defend your mentioning of this custom box with "there is way more scary stuff out there then what I mentioned," - just because there's other reprehensible violations of both the NEC and OSHA regulations, as well as good, common sense existing on construction/other sites, you still may not recommend a "not so dangerous but still illegal device" on these forums.

We need to be leaders in the entertainment field, making sure that we are doing everything we can to promote safe and responsible electrical practices!

Thanks--

Ray
you still didnt get it so never mind ! end of my discussion on that "homemade" box that a "consumer" can "legally" make because consumers in the USA "do not have to know or follow the nec". i or "anyone else" can use extension cords however we want. OSHA does not come around inspecting people houses and i "never" seen OSHA or any city electrical inspector come to a club and inspect a bands extension cords. that was my point, unless you are an electrician wiring a house or building you can do whatever you want with your cords and lights. this is a foto of a temporay kitchen light in my landlords house. my landlord put this up after the 4 foot flouresent fixture ballast smoked and burned up. his wife wants to look at lights this weekend so she can pick one out. this is temporary. is it hookey ? yes ! is it dangerous ? no ! i checked the tightness of the wire nuts. its 8ft on an 8 foot celing. would this pass an electrical inspection ? No ! can my landlord "legally" have this light like this ? yes , its legal "because" He put it up and its his house. if he were to sell the house he would have to put a light up thats up to code. the code does not apply to the consumer. abd thats my point. btw there have ben job sites that i have ben on that had the rubber pigtail light sockets wired just like this for temp lighting that are legal to have on a construction site. my whole idea got blown out of proportion and if i made the box and cords combo i was talking about it would be legal for me as a "comsumer" to do so. i know , i asked la building and safety and was told they dont get involved in the end user. just dont do what i suggested because you dont understand what i was talking about. buy larger guage extension cord. btw the foto of that light reminds me of my grandads hanging lights he had in his barns on his farm in the 1960's.