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Blew the breaker

What your local code refers to is something else. Since the required double pole breaker is also common trip, both circuits are shut off at the same time. There isn't any possibility of cross connecting to another live circuit of higher voltage in the same box.
 
I run a 15A and a 20A nearly dedicated outlets to my main stereo system. Amps are over 2000 watts/ch in total but I've never tripped a breaker yet. I do have some fluorescents in circuit with one of the outlets and used to dim them during peaks but have since balanced the amps better on the circuits and eliminated the dimming. I run 10ga Romex to the 20 amp circuit. Overkill is fine in my book.
 
whoaru99 said:
There isn't any possibility of cross connecting to another live circuit of higher voltage in the same box.
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My late brother could have F-ed it up. I have already had to fix some of his wiring nightmares.

I know what you're saying would work as well. But one outlet is already installed. So the easy fix is just add a second one on the same wall.
 
Gibsonian said:
I run a 15A and a 20A nearly dedicated outlets to my main stereo system. Amps are over 2000 watts/ch in total but I've never tripped a breaker yet. I do have some fluorescents in circuit with one of the outlets and used to dim them during peaks but have since balanced the amps better on the circuits and eliminated the dimming. I run 10ga Romex to the 20 amp circuit. Overkill is fine in my book.
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Nothing wrong with running 10ga wire on a 20A circuit to minimize voltage drop. Sorta a PITA to work with, but it certainly can and is done.

I have just over 8kW of QSC and Crown power in my garage system based on sound reinforcement gear. It all runs on one 20A circuit and achieves downright nasty SPLs. Have yet to trip the breaker but I don't kid myself that I'm maxing out the watts either. That said, it's still pulling some current on occasion. ;)
 
I can't understand how you can manage to trip a breaker with an amp. My 650 wpc Mac and 325wpc sub at obscenely loud levels manages to draw at best 5 amps on my power conditioner. This is with the power guard lights flickering.
Now plug in a vacuum cleaner or an electric heater and there goes 12+ amps. That doesn't trip my breaker but it sure does make the power meter spin. I'm thinking you've got other far more serious problems than too small a breaker.
 
purple1 said:
Last week I added another sub to the surround system. I had installed a dedicated 15 amp circuit just for this system. My son and I were cranking some tunes this weekend and we blew the breaker. It never happened till this sub got added. So I am going to upgrade this to 20 amps. Went to Home Depot and got 12/2 wire, breakers, and some 20 amp outlets. I'm replacing the 14/2 that is in use now. I figure I may as well run another 12/2 circuit while I'm running new wire. How many of you have a circuit (or 2) just for your system?
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I run two powered subs, 100W x 5 receiver, 200W x 2 amp, flatscreen TV, EQ for the subs, 2 cable boxes, and DVD player on a single 20A circuit and have never had a problem. According to the LCD display on my Belkin PF60 line conditioner, which everything is plugged into, current draw at normal listening levels does not exceed 7 amps. You guys must have been really cranking the system to pop the breaker.
 
grey said:
I have a single 20 and I'm planning another 20 (dedicated for sub) in the near future. Hopefully there will not be any loops. Isolation transformers on the signal line looks to be the cure if there are any problems. Has anyone had to do this?
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If you hook equipment up that is on one branch circuit with equipment on another branch circuit (which is more then likely going to happen), you will have the potential for ground loops thru their interconnects.

Wayner
 
purple1 said:
I think that would be a code violation. You should never have 220 in a 110 outlet box. What if some one that didn't know what you did worked on it later and hooked 220 to a 110 outlet?
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It's not really 220v. It's two phases of 120 in the same box. No one wire has over 120v on it, relative to ground or neutral.

What's happening, is that since they are opposite phases, the MAX current that the neutral has to carry, is when one circuit is at max, and the other is at zero. If the other circuit is carrying anything at all, its current will REDUCE the amount on the neutral wire (it will, in essence, "shunt off" some of the neutral current from the other phase).

We have a wall of our store, with outlets wired this way, wired by a pro, long ago. Two sets of outlets on two circuits, two hots, one neutral, one ground. It's standard practice, especially on long runs (saves cost, and is actually better for power transmission than separate neutrals, IIRC).

Regards,
Gordon.
 
purple1 said:
Last week I added another sub to the surround system. I had installed a dedicated 15 amp circuit just for this system. My son and I were cranking some tunes this weekend and we blew the breaker. It never happened till this sub got added. So I am going to upgrade this to 20 amps. Went to Home Depot and got 12/2 wire, breakers, and some 20 amp outlets. I'm replacing the 14/2 that is in use now. I figure I may as well run another 12/2 circuit while I'm running new wire. How many of you have a circuit (or 2) just for your system?
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In a house I used to own I had Two 20 amp lines for power amps, and one 20 amp for all the other stuff. At that time I had a pair of Manley Power amps that ran 10 6550's per amp, so they drew a few amps. Kirk
 
motorstereo said:
I can't understand how you can manage to trip a breaker with an amp. My 650 wpc Mac and 325wpc sub at obscenely loud levels manages to draw at best 5 amps on my power conditioner. This is with the power guard lights flickering.
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Try turning on two VAC Statement 450i tube amps at the same time. It will trip a 15 amp breaker. There's no surge limitation whatsoever in those amps (it was determined by extensive testing and listening that surge limiters, no matter what the type, adversely affected the sound of the amp)...

On another application (admittedly, pro, not home, audio)- we managed to trip a breaker a couple of times, until I determined that the power distro was mis-marked at one gig- and we had TWO Crown MA3602 amps (on subs) accidentally hooked up on the same breaker. Moved one of them to an unused breaker, no more problem...

Regards,
Gordon.
 
motorstereo said:
I can't understand how you can manage to trip a breaker with an amp. My 650 wpc Mac and 325wpc sub at obscenely loud levels manages to draw at best 5 amps on my power conditioner. This is with the power guard lights flickering.
Now plug in a vacuum cleaner or an electric heater and there goes 12+ amps. That doesn't trip my breaker but it sure does make the power meter spin. I'm thinking you've got other far more serious problems than too small a breaker.
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The problem is that amps produce a large current draw at turn-on. This, along with other, already on components, may bring a breaker to its limits.

Also remember that nuisance tripping will slowly lessen the circuit breaker's trip rating, and it will start to trip at less and less current, making it a PITA breaker.

Wayner
 
If running two circuits, I would keep separate neutrals, but share the ground. You can get interactions between the loads on a shared neutral, but it's more prominent on three phase systems where the legs are 120 degrees apart.
 
GordonW said:
It's not really 220v. It's two phases of 120 in the same box. No one wire has over 120v on it, relative to ground or neutral.

What's happening, is that since they are opposite phases, the MAX current that the neutral has to carry, is when one circuit is at max, and the other is at zero. If the other circuit is carrying anything at all, its current will REDUCE the amount on the neutral wire (it will, in essence, "shunt off" some of the neutral current from the other phase).

We have a wall of our store, with outlets wired this way, wired by a pro, long ago. Two sets of outlets on two circuits, two hots, one neutral, one ground. It's standard practice, especially on long runs (saves cost, and is actually better for power transmission than separate neutrals, IIRC).

Regards,
Gordon.
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They are not of opposite phase, since combining 2 voltages of opposite phase would result in an arc flash explosion. They are of the same phase. 120+120 (same phase) = 240 volts.

Wayner.
 
This problem can be approached in a little bit more of a scientific manor. The first step I would take is to gather information from each component that is going to be in these circuit(s). You need to know the maximum wattage draw from each device.

So, as an example, if your amp draws 1,200 watts, your preamp draws 13 watts and your CD player draws 7 watts, you would then add all the wattages up. That would then be 1220 watts. Divide that by the voltage (120) and the result is the current load: 1220/120 = 10.666 amps.

Now in your real life case, you might be drawing 17 or 18 amps (just guessing) so the 15 amp breaker is going to trip. You do need to determine the total amperage of your devices to figure out the next step.

You may only need 1 20 amp branch circuit and then your problems would be solved. You can put 15 amp outlets on the circuit, because no device you have has a 20 amp plug. The 20 amp breaker protects the wire from the breaker to the outlet, the outlet size protects itself from the plugged in device.

Your local electrician "might" let you put in a 120 volt, 30 amp breaker (using the appropriate gauged wire), but then none of the outlets can be wired in parallel to each other, all must go to an appropriately sized terminal block, to handle the load. They do make single space breakers, just don't know if the local inspector would frown or not. You would need a separate box for the terminal block (and connections). We could do this in industrial design, not sure what an inspector might say for home use. I see no reason why not.

This 30 amp circuit would give you all the power you should need and have the single ground, to eliminate ground loops. These are questions you need to ask your local electrician guy/inspector

Wayner
 
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WaynerN said:
Your local electrician "might" let you put in a 120 volt, 30 amp breaker (using the appropriate gauged wire), but then none of the outlets can be wired in parallel to each other, all must go to an appropriately sized terminal block, to handle the load. They do make single space breakers, just don't know if the local inspector would frown or not. You would need a separate box for the terminal block (and connections). We could do this in industrial design, not sure what an inspector might say for home use. I see no reason why not.

This 30 amp circuit would give you all the power you should need and have the single ground, to eliminate ground loops. These are questions you need to ask your local electrician guy/inspector

Wayner
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Not exactly sure of the connection method you're describing, but it would seem that NEC 210.10 precludes connecting 15A or 20A receptacles to a 30A circuit.
 
There is no danger of damage. 30 amps is the capacity of the circuit. It's like having a 10 gallon bucket of water with a pin hole in it or a 5 gallon buck with the same size pin hole in it. The device connected to it draws the current it needs, the 30 amp circuit does not force 30 amps down the devices throat.

Wayner
 
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