AVS Forum banner

1 - 20 of 44 Posts

·
Registered
Joined
·
2,053 Posts
Discussion Starter #1
Thanks to a really wet summer last year, I get to rebuild my basement (bassment). As such, I have the opportunity to rewire everything. I have two large spools of 12g and 14g electrical wire, so is there any reason not to just redo everything with 12g and use 20-amp breakers instead of 14g/15a? I figure that with all the electronics I'm driving (some higher amps than others), it couldn't hurt. Thoughts?

15Ax120V=1800Wx80%=1440W
20Ax120V=2400Wx80%=1920W
 

·
Registered
Joined
·
12,853 Posts
Nope, I'd do it. Although you might save the 20 A for key circuits (bedroom probably does not need it, media room yes). Depending on your codes there may be an issue about service capacity if you run 20 A everywhere. In our area 14 AWG is used for 15 A, 12 AWG for 20 A circuits. Note 20 A circuits use a different outlet but it is compatible with standard wall plugs.
 

·
Registered
Joined
·
2,053 Posts
Discussion Starter #3
Nope, I'd do it. Although you might save the 20 A for key circuits (bedroom probably does not need it, media room yes). Depending on your codes there may be an issue about service capacity if you run 20 A everywhere. In our area 14 AWG is used for 15 A, 12 AWG for 20 A circuits. Note 20 A circuits use a different outlet but it is compatible with standard wall plugs.
Right. I wasn't able to find any issues with city/state code, but I figured since some of these speakers hit over 2000W peak (on paper), it couldn't hurt anything to overbuild - other than my wallet.
 

·
Registered
Joined
·
115 Posts
I would definitely do it. I recently moved into a new house (22yrs old) and I have 2 SVS PB13U subs and when the volume goes up the lights start dimming to the beat. I'm an electrician and if I could I would run 20 amp circuits everywhere in possible media room areas anyway.
 
  • Like
Reactions: oneeyeblind

·
Registered
Joined
·
12,853 Posts
Check the service (breaker box) rating. If you put five 20 A breakers into a 100 A service box you are at capacity. It is fairly common to have a lot more than the service rating in breakers but that is one thing I would double-check.

When we finished our basement I had three 20 A lines run to the media plus one more to the exercise/storage room for our treadmill/clothes hanger/box holder. Everything else is standard 15 A lines.
 

·
Banned
Joined
·
15,491 Posts
Check the service (breaker box) rating. If you put five 20 A breakers into a 100 A service box you are at capacity. t is fairly common to have a lot more than the service rating in breakers but that is one thing I would double-check.
The number of breakers doesn't matter, the assumption being you'll not run all of them at capacity at the same time.
FWIW standard practice for decades has been to wire outlet circuits at 20a, using 15a only for lighting circuits. High draw areas, like kitchens, usually get at least two separate 20a lines.
 
  • Like
Reactions: oneeyeblind

·
Registered
Joined
·
12,853 Posts
The number of breakers doesn't matter, the assumption being you'll not run all of them at capacity at the same time.
That's what I thought but apparently there's a limit in some areas. I live in the county and it didn't matter, but our electrician said it did matter in some areas (towns? I didn't ask...) I was discussing adding a transfer switch at the time since we lose power fairly often (several times a year, sometimes for an hour, sometimes a day) and asked abut service ratings. I do not recall the limit, seems like it was pretty big, like 250 % or more of the total service rating. It was five-plus years ago so my memory is a little foggy.

FWIW standard practice for decades has been to wire outlet circuits at 20a, using 15a only for lighting circuits. High draw areas, like kitchens, usually get at least two separate 20a lines.
All the wiring I have seen in recent years (out here and in MO, only places I've been where I've dealt with it anytime recently) uses 14 AWG for standard outlets and supposedly that is only good for 15 A outlets. When I asked for 20 A they upgraded to 12 AWG and warned me at the time I would pay extra for the 20 A runs. AFAIK 14 AWG will support 20 A runs in a house (i.e. not transmission lines, just inside the house). Decades ago when I was a Journeyman 12 AWG was used everywhere for residential (except stove/range/dryer/HVAC high-current stuff). I was told the major reason for the change to 14 AWG was copper cost. The 20 A outlet is different, adds a side slot, but works with regular 15 A plugs. 30 A is a different plug (usually).

I am sure it varies from place to place and I have not looked at the actual national (NEC) regs for ages.
 

·
Registered
Joined
·
11,697 Posts
I figured since some of these speakers hit over 2000W peak (on paper), it couldn't hurt anything to overbuild - other than my wallet.
Even on the 15a circuits I'd put 12awg (if you wanna). Consider it future-proofing.

I have 2 SVS PB13U subs and when the volume goes up the lights start dimming to the beat. I'm an electrician and if I could I would run 20 amp circuits everywhere in possible media room areas anyway.
I have dual 2awg and have the same problem, when the amplifiers pull 43kW through the wire, the lights dim. In fact I might be browning out the whole hood... hehe :p
 

·
Premium Member
Joined
·
5,644 Posts
My basement layout.
1- 20amp circuit for the bar area
1 -15 amp circuit for the bathroom
1-15amp for lights main area in basement
1-15 amp for outlets main basement area
2-20 amp circuits for HT room rack
1-15 amp circuit for the HT rack
1-15 amp circuit for HT room lights
1-15 amp circuit for HT outlets

I have a 200 amp breaker that I went off of and I don't see any problems with that lights which are going to be led or cfl and not everything will be running all at the same time and if there were a breaker would trip. just my 2 cents on this.
 

·
Premium Member
Joined
·
1,312 Posts
MAIN SERVICE PANNEL

If you add up all the breakers in your main service panel, it is normal for the total to exceed the rated capacity of the box. That is because it's assumed that you will not be using all circuits at their full capacity at the same time. When the house is built, a load calculation is done on all the appliances, AC, outlets and lighting loads that might be in use at the same time to determine the size the main panel.

WIRE

The breaker size and wire gauge for each circuit are determined by the type of load. The rule of thumb is that nominal load should not exceed 80% of capacity. Therefore, for convenience outlets you typically run 12 awg wire capable of 20 amps even if the breaker and receptacles are rated at only 15 amps. It's not uncommon to run 12 awg wire to a switch box with multiple 300w/600w dimmers then run 14 awg on the switch leg from each dimmer to the lighting loads.

THNN solid core wire will carry a greater maximum amperage than stranded wire. It's always easier to run 12 awg wire and limit the circuit to 15 amps with the breaker and receptacle, than to decide later you want 20 amps and re-pull wire through a crowded conduit or Romex through walls under sealed drywall. Your time and labor are much more expensive than the cost difference between 12 and 14 AWG.

BREAKERS

Think of electricity like water. It comes in from the street on two hot wires (phase one & phase two) and then returns to the source through one common wire. The local utility sends a 110v pulse on phase one, then a 110v pulse on phase two, then back to 110v on phase one, and so on. In your Main service panel there are two sets of copper rails for phase one and phase two. A 110v "single-pole" breaker will snap onto only one rail, a 220v "double-pole" breaker will snap onto both rails.

Breakers come in different configurations: (1) Half size 1/2" single pole , (2) Full size 1" single pole or double pole (3) Twin 1" two single pole, and (4) Quad size 2" four single, two double pole or a combination thereof. When you add a circuit, you simply pull out one or more Full size breakers and replace them with Twins or Quads to free up one or more unoccupied terminals.

PHASE

Phase is important to keep track of because typically you will run three wires (two hots and a common) from the main panel to a given location. Each hot wire is on a different phase and they share the common wire with the current alternating between them. if you get your commons mixed up at the end location, you can have two hots trying to drain through the same common and overheat the common wire. You can also get voltage feeding back through dimmers or an adjacent load if you don't keep track of which common goes to which load.

Typically electricians run black for phase one, red for phase two, and white for the common to keep track of phases at the end location, using colored wires to differentiate switch legs or branch circuits. Typically, I will run all my hots and commons in red, black and white to a junction box in the Theater area, then make it up with colored wire pulled to the various receptacles.

AUDIO

For audio equipment, especially power hungry amplifiers, I always run 12 awg, with 20 amp breakers and 20 amp receptacles. There are expensive audiophile receptacles from PS Audio and others, but a standard hospital grade outlet from your local electrical supply is more than comparable.

When running multiple amplifiers in home theater, it's important to do a load calculation and distribute the amplifiers over a sufficient number of circuits. You can get the maximum current draw of each amplifier from the specifications in the owners manual or by calling the manufacturer's technical support. Remember that the rule of thumb is 80% load to capacity. A receptacle wired for 20a/110v is rated for 2200va, so two amplifiers rated at 850va each will just about use up one 20 amp circuit.

Many high power multichannel amplifiers can easily take up a 20 amp circuit on their own. Multiple subs in an installation can also require one or more circuits (although the newer class D amps may use less power than a traditional class a/b amp). If possible, keep the electronics and video on a separate circuit so that they are not effected by a surge in demand from multiple amplifiers during demanding special effects.

GROUND LOOPS

Ground loops occur whenever the grounding potential one receptacle location is significantly stronger than another. They can be difficult to track down and aggravating to eliminate. To preempt ground loops when I pull wire for a theater, I usually pull a 12 awg green ground wire along with my hots and commons (or the bare copper ground wire in Romex) from the receptacles in the theater room to the Theater central junction box. From there I wire nut them to a 10 awg stranded green wire back to the ground block in the main panel. Most main panels have a heavy gauge wire connecting their grounding block directly to a nearby long copper rod hammered deep into the ground. This guarantees that the grounding potential for all receptacles is greatest at one common point at the theater junction box.
 

·
Premium Member
Joined
·
1,312 Posts
DWP had two 100 amp drops to our house, one for the main panel and one for the 30 amp AC. After doing a load calculation I installed a new main panel on the second 100 amp drop and ran about 50 feet of 2" conduit to a sub-panel in the AV closet. Then I pulled 3 dedicated 20A/120V circuits using 10 awg stranded wire for three subs, 4 dedicated 20A/120V circuits using 12 awg THNN wire for eight amps, 2 dedicated 20A/120V circuits using 12 awg THNN wire for audio and video electronics, and one 20A/120V circuit using 12 awg THNN wire for regular wall outlets and to power 12 Martin Logan Electrostatic speakers.

Our theater is part of a 1,200 sq ft open floor plan with 5 dedicated 20A/120V circuits using 12 awg THNN wire for 5 Lutron Graphic Eye 6-zone dimmers for recessed halogen lighting. All of the electrical outlets in the theater have isolated grounds home run with 12 awg THNN to the sub-panel, then back to the main panel with 10 awg stranded to eliminate ground loops.

I took a class at CEDIA one year from the head designer at Fuhrman who recommended keeping all a/v branch circuits on the same phase. So every hot wire for the amps, subs, electronics and video has its own dedicated common wire so that all breakers for the theater can be on the same phase at the main panel.
 

·
Registered
Joined
·
1,319 Posts
Hey thanks for the electrical 101. I am about to run a couple dedicated lines to my family room for the new subs I have on order. Right now everything (64" plasma TV, My Amp and Pre-amp, BR, and all lights are coming from a single 15a breaker. I put a plug in amp load tester and I am only drawing about 6 amps the most. But the subs I am getting has 2400w amps each, so I think that will be pushing it. And I want to bridge my McIntosh amp latter and use it for the LCR channels that will be 320w per channel and get a 2nd amp for the surrounds and may some heights. I was told the sub amps are very efficient and would probably run just fine on 15 amp. But I am not sure with everything else. I could also run the amps on 230V, but I was told there is no real advantage as long as there is no voltage drop. And I think that is an important thing to think about when running wire. The longer the wire, the more of a voltage drop right? I even thought about running a 10/3 wire, just in case I ever wanted to go to 230V then the wire would be there and just not use the one leg for 110v. But I will have to run this from my garage to my family room in a pre-built house, so trying to fish 10g wire might be a bit of a headache. Im just trying to decide if I want to tackle this myself or hire an electrician.
Also, my breaker box has about 330 amps of breakers in it now and they are all full. So I guess I would have to use one of those tandem breakers to free up some slots. I have no idea what my main breaker is! There is no making on it. The box I believe is a 20-20. So I don't know if I need to upgrade the box or not. A lot of unknowns. Would a electrician want to hook up the wires at the box and check or hook up the receptacle if I run the wire and do all the labor intensive work? Or would he be worried of a liability issue?
 

·
Registered
Joined
·
1,319 Posts
I got a question. I had 2 electricians come out and give me a estimate on finishing my twin 20A circuits I am installing for the Home Theater System. One of them is bypassing the permit and just using standard 20 amp breeakers. The other will only do it with a permit, and says I will have to use AFCI breakers. I read some reviews of people having trouble with Arc Fault breakers tripping too easy. But so far its been either a Microwave or vacuum cleaner. Has anyone used the AFCI breakers for the high powered amps? And if so, any problems?
 

·
Banned
Joined
·
15,491 Posts
AFCI protection, via either the breaker or outlet, is required as of 2014 by the NEC. However, the NEC isn't locally binding. Local standards are set by individual states and municipalities. They may adopt NEC standards, but they may not. When in doubt as to what you must have check with your local code enforcement officer.
 

·
Registered
Joined
·
12,853 Posts
+1. They are required in my county as of a few years ago, not in some other areas. We had problems with one flipping in our boy's bedroom when our treadmill (in a different room, on a different breaker) was cycled. Both are on a basement sub-service. The media room breakers did not trip (for 15 A outlets; dedicated 20 A outlets did not have them). Same service, might be on a different phase (not sure at this point). The offending AFCI breaker was replaced a couple of times and then I put in a regular breaker. Not code, but kept my boy from being in the dark.

At that time, in our area, they were required in certain rooms but not all (bedrooms; kitchen/bath had GFI, etc.) And, they were not required on my 20 A dedicated lines in the media room, or at least that's what the electrician told me. It passed inspection, who knows... Our county's website was very helpful, as was the inspector's office.
 

·
Registered
Joined
·
1,319 Posts
I will just have to take the electricians word for it. I went and picked up 2 - 20A AFCI's at lunch. It seems like a good idea. I just think the technology isn't there yet. But, if I have trouble with them tripping after its inspected, then I will just replace them with a standard breaker. I will also ask the inspector when he comes out to do the inspection if I really need them for the family room.
 

·
Premium Member
Joined
·
1,312 Posts
Hey thanks for the electrical 101. I am about to run a couple dedicated lines to my family room for the new subs I have on order. Right now everything (64" plasma TV, My Amp and Pre-amp, BR, and all lights are coming from a single 15a breaker. I put a plug in amp load tester and I am only drawing about 6 amps the most. But the subs I am getting has 2400w amps each, so I think that will be pushing it. And I want to bridge my McIntosh amp latter and use it for the LCR channels that will be 320w per channel and get a 2nd amp for the surrounds and may some heights. I was told the sub amps are very efficient and would probably run just fine on 15 amp. But I am not sure with everything else. I could also run the amps on 230V, but I was told there is no real advantage as long as there is no voltage drop. And I think that is an important thing to think about when running wire. The longer the wire, the more of a voltage drop right? I even thought about running a 10/3 wire, just in case I ever wanted to go to 230V then the wire would be there and just not use the one leg for 110v. But I will have to run this from my garage to my family room in a pre-built house, so trying to fish 10g wire might be a bit of a headache. Im just trying to decide if I want to tackle this myself or hire an electrician.
Also, my breaker box has about 330 amps of breakers in it now and they are all full. So I guess I would have to use one of those tandem breakers to free up some slots. I have no idea what my main breaker is! There is no making on it. The box I believe is a 20-20. So I don't know if I need to upgrade the box or not. A lot of unknowns. Would a electrician want to hook up the wires at the box and check or hook up the receptacle if I run the wire and do all the labor intensive work? Or would he be worried of a liability issue?
10/3 wire is really overkill. You should be fine with 12/3 Romex.

Voltage drop on 100v is not really an issue if you plan your load to be 80% of capacity (i.e. about 1,800 watts on a 20 amp line).

I have found AFCI's to be a pain in the ass on exterior loads where dampness creates some grounding issues. They also tend to trip on variable motor loads (when the motor first starts up, it pulls a lot of amps to overcome inertia). I haven't used then for a HT so I don't have direct experience with AFCI's and power hungry amplifiers.

You can save a lot of money by running the Romex, mounting the j-boxes and terminating the outlets yourself and have the electrician terminate the wire at the main panel. It's easy, there are DIY videos on youtube and picture books at Home Depot. Just use Romex staples to secure the lines, always drill your holes through studs in the middle and leave more than enough romex at the end looped up so he's not short on routing the wire in the main panel.
 

·
Registered
Joined
·
1,319 Posts
I went with 12-2 romex (not counting the ground wire) since I decided to stick with 120V. The electrician said it had to be stapled every 4 feet. But I did it on each rafter. I had a box of them so what the heck. I just finished shoving all the wire I need to behind the outlet and have all wire in the attic stapled except about 10 feet before it drops to the service panel. I don't know if its matters, but I took the time to make the wire run nice and straight and kept the wire flat without any twist.
The Electrician is charging me $201 ($133.50 for time + $52.23 for permit + $15.60 tax) to run the wire from the attic down to the panel and install the new breakers and wire it up.

The panel says 2020, but I found out that it can us 40 circiuts ( 20 of the narrow 1/2" breakers ). GE doesn't use the tandem or duplex breakers, they use a half width breaker instead.
 

·
Registered
Joined
·
4,347 Posts
If you want to go nuckin futs... I would add a 30 amp breaker in the media closet just in case you want to buy yourself a "mega" amp for huge subs. I have at least 5 15 amp outlets leading to my closet as well.

Additionally I have a blind ended outlet going to from my media closet to my projector area. This way I can plug in the projector into my furman balanced power conditioner where everything else is plugged in. eliminates the possibility of ground loops.

I believe no room should ever be designed without quad DIY subs with high power rack mount amps. Epic bass that is relatively cheap, hidden, easy to build.
 

·
Registered
Joined
·
3,357 Posts
One rule of thumb I would recommend to those running Romex: Use three-conductor Romex. This will permit two 20-amp circuits at one location, if needed. Opposite-phase circuits with (hopefully) somewhat balanced loading and reduced neutral (white wire) current and the ability for a 220-volt connection, if required.
 
1 - 20 of 44 Posts
Top