long power cable run

hurtz · #1 02-06-2011, 10:23 AM

I have recently played at a location that required a long extension cord to my amp. The clip light on my head was illuminated the entire gig. I was concerned about my amp but I didn't have time to address the problem.
Will this damage my amp? What can I do in the future if I am faced with the same situation?
Thanks

mcnach · #2 02-06-2011, 10:25 AM

are you saying you think there's a link between the extension power cord and your amp's input clipping?

DerHoggz · #3 02-06-2011, 10:30 AM

As long as it is a good extension cord it won't matter, there is already a really long cord from the electrical box to the outlet.

Nev375 · #4 02-06-2011, 10:31 AM

Depending on where you are and the particular extension cord you are using, you probably have better electrical conductivity between the plug-in and your amp than between the plug-in and the power plant.

saxofunk · #5 02-06-2011, 10:37 AM

It's possible, if your amplifier pulls a lot of amperage. The fix is to get a heavier gauge extension cord. Determine the amp draw of your rig and match it to this chart. I've run into this with power tools, voltage drop can cause motors to overheat and die young.

hurtz · #6 02-06-2011, 10:47 AM

Thanks for the quick reply! Ive never had the clip light on continuosly like that before or since that event and the volume wasn't crazy high. it wasn't my extension cord so I don't know the quality of it. I will try buying a heavyer gauge extension cord for that purpose.
Thanks!

Darylt · #7 02-06-2011, 10:57 AM

saxofunk is giving good advice here - the general rule of thumb is for every hundred feet run up your wire size one guage. Assuming your starting with a 14 guage, if not get a cord that is minimum 14, preferably 12. If your amp is drawing anything in the 10 amp range and your using an 18 guage cord - which typically they are - you will eventually get pre mature wear on your amp with extended use, and your cord will wear out earlier which isn't near as bad as your amp...

billfitzmaurice · #8 02-06-2011, 12:54 PM

Quote:

Originally Posted by hurtz

I have recently played at a location that required a long extension cord to my amp. The clip light on my head was illuminated the entire gig.

The likelihood of the two being related is extremely slim. Perchance was this an outdoor gig?

hurtz · #9 02-06-2011, 01:15 PM

Quote:

Originally Posted by billfitzmaurice

The likelihood of the two being related is extremely slim. Perchance was this an outdoor gig?

yes it was an outdoor gig. I assumed it was from the slow power draw. What caused it?

44me · #10 02-06-2011, 01:58 PM

I think Bill's identified the main problem. Sizing the main power feed to safely handle the current is not the same as sizing it to properly deliver rated voltage under load. This problem is pretty common at outdoor gigs as well as construction sites. A suitably sized extension cord keeps you from exacerbating the problem, but doesn't fix it. I carry a heavy gage, 25' extension cord with me. As far as I'm concerned, anything longer than that is the venue's responsibility.

anonymous122511 · #11 02-06-2011, 02:21 PM

Quote:

Originally Posted by 44me

I carry a heavy gage, 25' extension cord with me. As far as I'm concerned, anything longer than that is the venue's responsibility.

LOL!
It's their responsibility until they don't have one then it's YOUR PROBLEM.

Jim Campbell · #12 02-06-2011, 02:31 PM

Quote:

Originally Posted by hurtz

I have recently played at a location that required a long extension cord to my amp. The clip light on my head was illuminated the entire gig. I was concerned about my amp but I didn't have time to address the problem.
Will this damage my amp? What can I do in the future if I am faced with the same situation?
Thanks

you can buy hospital/good quality plugs and bulk cable and make up a 50 footer.....the ten dollar extensions get hot to the touch when you start to draw on them and the molded ends cannot be repaired...... heavier gauge wire for longer runs.....personally i use good ones for everything,as i have this phobia about burning alive over a cheap extension,but that's just me

billfitzmaurice · #13 02-06-2011, 02:55 PM

Quote:

Originally Posted by hurtz

yes it was an outdoor gig. I assumed it was from the slow power draw. What caused it?

Outdoors it takes roughly four times the power for the same output, so you were playing louder even if you don't think you were. Generally you need to take twice the usual cab count for outdoors.
BTW, long extension cords and outdoor gigs are a formula for trouble, especially if you're not on a wooden stage. Rule of thumb, if you have to use more than a 25 foot extension to a grounded service entrance box don't accept the gig. And make damn sure they have proper power before you show up for the gig. This rules out many informal outdoor party gigs, but no gig is worth dying for.

Pilgrim · #14 02-06-2011, 03:26 PM

If the AC cord got hot, then you were drawing power through it in excess of its safe capability, and need to get a cable with heavier gauge conductive material.

I did some research online and found a few recommendations that if you are drawing as much as 15 amps (that's the load rating on many residential circuits) you should be using 14-gauge wire.

Here's a cut-and-paste from another forum where this was discussed:

25ft extension cords are generally UL rated at:

18 gauge: 10 amps (@ 120V = 1200W)
16 gauge: 13 amps (@ 120V = 1560W)
14 gauge: 15 amps (@ 120V = 1800W)

Most of what you buy over the counter for homeowner use is either 18 or 16 gauge. You have to hunt for 14. Home Depot sells a 50-foot 14/3 extension cord for $19.66, and a 50-foot 12/3 extension cord for $44.87. A 12-gauge cord will handle just about any amp made.

anonymous122511 · #15 02-06-2011, 04:05 PM

Quote:

Originally Posted by Pilgrim

If the AC cord got hot, then you were drawing power through it in excess of its safe capability, and need to get a cable with heavier gauge conductive material.

Also on the subject of heat if you have an excess of AC cable more than a few feet DO NOT COIL IT. A coil makes a nice heating element similar to what you'd find in a toaster. If you wanna make excess AC neat figure 8 it. This holds more true for lighting systems as you have to have a pretty wimpy cable or a fault of some kind to generate much heat from what a bass amp draws...a bar room PA and stage gear should in most cases run comfortably on 30 amps. Use hospital grade plugs and 14/3 water jacket for your cables and you will never have a cable related AC issue.

Bassmec · #16 02-06-2011, 06:19 PM

Quote:

Originally Posted by hurtz

I have recently played at a location that required a long extension cord to my amp. The clip light on my head was illuminated the entire gig. I was concerned about my amp but I didn't have time to address the problem.
Will this damage my amp? What can I do in the future if I am faced with the same situation?
Thanks

Tour in the UK and europe, we have proper electricity over here, not that half arse'd US stuff.
We can pretty much get away with using damp salty string for extensions.
Don't bother with Japan at all, they only have 100 Volts of stock
juice, hardly enough for real rock and roll!.

44me · #17 02-07-2011, 08:09 AM

Quote:

Originally Posted by jeff arddun

LOL!
It's their responsibility until they don't have one then it's YOUR PROBLEM.

We all have the draw the line somewhere. Assume a professional relationship, and chances are, that’s how you’ll be treated. On more than one occasion I've told the sound manager that the band can't go on until adequate power is supplied (it's something I check for as soon as I arrive). There's a little scrambling, and then somehow they find a solution. You can circumvent this to some degree by putting power requirements into your contract, particularly for outdoor gigs. At the very least, email the guy that’s booked you for an outdoor gig and make it clear what your requirements are (such as minimum power feed and maybe overhead protection for your gear).

jeffbrown · #18 02-07-2011, 08:22 AM

Getting a little OT - Coils in power cables can also cause trouble for audio, as in creating an AC (60 cycle) hum in audio cables/gear nearby. And try not to run power right alongside audio for the same reason. If you must run power near audio, try to cross them at right angles, or better yet, elevate one or the other. "Yellow Jackets" or cable troughs for cables are pricey, but they work well for outdoor venues or other high-traffic locations. And then there's audio snakes, et., etc.

But +1 for heavy gauge cables!

BurningSkies · #19 02-07-2011, 09:03 AM

Quote:

Originally Posted by Bassmec

Tour in the UK and europe, we have proper electricity over here, not that half arse'd US stuff.
We can pretty much get away with using damp salty string for extensions.
Don't bother with Japan at all, they only have 100 Volts of stock
juice, hardly enough for real rock and roll!.

As always, a great solution.

Bob Lee (QSC) · #20 02-07-2011, 07:56 PM

Without knowing how long is "long" (25 feet? 2000?), I'll have to agree with Bill Fitzmaurice that playing outdoors tends to require a lot more power than indoors, so you were probably just pushing it a lot more than you usually do.

Loops in an extension cord aren't as bad as some make them out to be.