What size wire and what is the power draw?

[Coytee]

Setup:  I might be putting some stuff together to create an outdoor event.  I will likely have the MWM's on the bottom, Peavey MB's in the middle and the K402's on top in a 3-way, active setup.

 

Amps will likely be three Crown K2's doing horizontal triamp duty.

 

I haven't measured yet but let's say distance is no more than 200 feet from house.  Probably less but we'll use 200' for conversation.  (I'll probably buy 50 or maybe 100 foot lengths of speaker wire so I can shorten the wire to the house if the speaker wire is a bit longer)

 

Looking to take (for example since I'm not sure of size needed) a 10-3 with ground wire.  Put one leg onto a (15? 20?) circuit breaker.  Put the other leg onto the other side (double pull breaker) creating what on the surface seems to be a 220 volt situation however, then run the common leg back such that each hot leg is a 110 volt and the common is shared, giving me ....how to word it....  essentially two 110 volt lines inside one wire.

 

Stretch this out to the field and setup a table with the Crown amps, a preamp, active crossover and a DVD or CD player.

 

1.  I don't have access to a generator and a generator will create a lot more noise than I want.

2.  I need to get my garage wired so if I can use 12g wire, I'll not be wasting any cash since I can use this wire for garage purposes!

3.  This will be for a one or two time event (unless it's a smash hit)

 

I was told I should instead, use a transformer to step up, then down the power from the house so I could use a smaller distance wire (thoughts?)

 

I was also told by someone else that a transformer is a waste....that you don't have that much drop in power over the distance (said by my brother in law who can see the distance and is an electrician)  I think he initially thought I could use 12g wire without knowing how much current I needed for the Crowns

 

I'm trying to find the power draw of the Crown's and so far (looking on their back) don't see it.  Anyone know what they pull?

 

Travis, if you're reading this, yes....  I'm already trying to lay out plans for the E'Klipsch in August!  I intend to do a dry run prior to discover and work out any bugs.

 

 

[minermark]

7 minutes ago, Coytee said:

creating what on the surface seems to be a 220 volt situation however, then run the common leg back such that each hot leg is a 110 volt and the common is shared, giving me ....how to word it....  essentially two 110 volt lines inside one wire.

I dont think you want to do it that way.

Your brother in law is an electrician? buy him his Fav Beer and have him take care of your power.

There is no "Share" of a Neutral.

10Ga is a good choice.

[Coytee]

 

7 hours ago, minermark said:

I dont think you want to do it that way.

Your brother in law is an electrician? buy him his Fav Beer and have him take care of your power.

There is no "Share" of a Neutral.

10Ga is a good choice.

 

Why so?

 

My understanding is each leg will be on a different phase at the panel so the common (or neutral if that's the right term) on the 'return side' would see each phase of the 110 volts but at alternating pulses.  The two hot leads would only see 110 volts each.  You end up with essentially two 110 lines at the outlet box (I'd have to have multiple outlets)

 

By the way, it was my brother in law who brought this up!

 

It was another guy (electrical sales supplier guy) who said instead, I might try a transformer to step up at the house, then step down in the field.

 

I'm a simpleton....but I (think) I can understand why both would work.

 

Again, keep in mind, this is for say, 6-10 hours of use, this isn't any type of installation.  Just a way to have some power 200 feet away from the house without the noise of a generator humming nearby.

[Don Richard]

52 minutes ago, Coytee said:

My understanding is each leg will be on a different phase at the panel so the common (or neutral if that's the right term) on the 'return side' would see each phase of the 110 volts but at alternating pulses.  The two hot leads would only see 110 volts each.

 

240 V house power is single phase, so no alternating pulses. I would run one 10 ga. extension, wired conventionally, and plug both amps into that. The current draw will be low because of the transient nature of music, should sound good.

[Davis]

120/240V/2P/3W is the common house service from your utility company.

It is referred to as single phase but is technically 2phase.

The 2 pole (2P) nomenclature is for pole not phase.

The 3 wire (3W) nomenclature is 2 phase wires and a neutral with the ground wire not accounted for but present.

It was common practice before the NEC 210.4(B) change to share a common neutral between 3 phases (ABC) circuits to obtain three 120V circuits in commercial applications.

In your example you could share a common neutral with a 2 pole circuit breaker to obtain two 120V circuits but it would be a code violation. This would work because the 2-pole breaker will be connected to the A and B phase)

If you tried to use two separate 1 pole breakers with a common neutral and both were connected to the A phase for example this would not work. The same result would occur.if you tried to use two B phases together.

 

Your example of a 200 foot #10AWG copper 120V circuit with a 3% voltage drop would allow for a 7.5 amps maximum load.

 

For safety concerns I recommend you stick with two dedicated 120V circuits and do not introduce any step up transformers into the application.

[minermark]

Yes, exactly what Davis says here.

You stating you have an onsite Electrician, im stating use him.

Always easier learning Code wile doing it with a qualified person

[rbrown0678]

Your voltage drop would be my main concern since the conductor is able to carry more amps than the breaker, 

Just for peace of mind you could run #10/2. This would then be a over kill, for re-use in garage rewire tho

doable.

Use the 10/2 as a  120v ck, from source and using 2 inline  15 or20 amp fuses, from hot tie to two receptacles to feed eqpt. Pigtail neutral to outlets.also ground,  #10 may be control by 25/30 amp breaker. That's what I'd do  

 

 

[Coytee]

I'm ok with over-kill.  Heck, we're all on the Klipsch forum.... I think to a degree we're all into a bit of overkill!

 

9 hours ago, Davis said:

In your example you could share a common neutral with a 2 pole circuit breaker to obtain two 120V circuits but it would be a code violation. This would work because the 2-pole breaker will be connected to the A and B phase)

If you tried to use two separate 1 pole breakers with a common neutral and both were connected to the A phase for example this would not work. The same result would occur.if you tried to use two B phases together.

 

Although that is what I was thinking....I don't think I phrased it as nicely, thank you!

 

I knew they had to share a breaker to be on the different phases.

 

Now, I have to figure out how to get about 8-10 outlets on the end of this wire.

 

I expect to have:

 

Three Crown K2 amps

One preamp

Two active crossovers

One CD player

and/or

One DVD player

 

That gets me to eight plugs.  I think that would do it but, every time you think you've figured it out, you get a curve thrown at you!!

 

So, I will probably shoot for 5 duplexes, 10 outlets.  Put 2 on one phase and 3 on the other phase.

 

I have a feeling that the breaker/wire/panel box interface will be the easy part....  the 5 duplexes on the other end, wired to (what I anticipate to be) 10g wire might be the real bugger.

 

 

[JohnA]

http://www.stayonline.com/reference-circuit-ampacity.aspx

 

The neutral will carry twice the current of the "conductors" in your proposed configuration.  Don't.  Use a 10/4 with ground.  Make 2 "positive" and 2 "negative" and have a safety ground. 

[babadono]

What you want to do should be fine. Put 2 of the K2s on one line and the other K2 and all the other relatively low current draw stuff one the other. In fact if the loads on each side are equal there will be no neutral current. Just don't do anything stupid like think you can do it without a ground.