If you are trying to wire a circuit yourself and wondering how many outlets you can install on a circuit this article will help. Read on
You can legally install 12 outlets on a circuit of 15 amp 120 volt. This includes light boxes as well as plugs so make sure you count them. You do not have to include smoke detectors in this count.
How Many Outlets Can You Install On A Circuit?
You can install up to 12 plugs or light fixtures on one circuit.
Each outlet box or device box is considered to be a power point. This also applies to octagon light boxes.
A word of caution when you max out a circuit to 12 devices be careful what you plan to plug into the circuit. We often max out plug circuit to minimize the use of arc fault breaker‘s.
This is because they are so expensive. Our code states that we must use arc fault breaker’s on plug circuit in a residential dwelling. We often break up the light circuit from the plug circuit because the light circuit does not require an arc fault.
Although you can max your plug circuit out to 12 devices we do not recommend it. Most modern plug-in appliances will consume most of the circuit for example a vacuum cleaner.
This will cost nuisance tripping issues.
How Many Outlets Can You Install On A Circuit Of 14/2 Wire?
As mentioned above you can install up to 12 devices on a circuit. This also applies for 14 two wire.
14 /2 wire is the most common size wire used for wiring electrical devices. 14 /2 wire is rated for 15 A. You should not load the circuit up to more than 80% of its capacity.
This would be 12.5 amps. So that is where the 12 devices coming from.
How Many Outlets Can You Install On A Circuit Of 14/3 Wire?
Similar rules apply for 14/3 wire you can still only run up to 12 devices on a piece of number 14/3.
Most times 14/3 wire is used on circuits to switch one haf of the outlet. This is a very common practice in large rooms that do not have a ceiling lighting.
It is used for switching lamps around the room from one switch location.
One point you could use a piece of 14/3wire for a power feed. In this case you could divide the two circuits up from the 14/3 to give you 12 on each which would be a total of 24.
In a new code they came out with a rule that we are no longer allowed to supply circuit with a 14/3 wire.
They must all be now 14/2 wire. We still use 14 /3 wire for switching outlets as mentioned above as well as three-way and four-way switching applications.
Does It Make A Difference If i Use 12/2 Wire?
It does not make a difference if you use 12 gauge. You can still only use 12 devices on the circuit.
Although this wire is rated for 20 amp instead of 15 amp the electrical code needs to have some sort of consistency.
14/2 Wire is more cost effective so you might as well make use of it.
We do use 12/2 wire all the time in commercial applications. This is because commercial devices usually draw more power.
Why Do I Not Need To Include Smoke Detectors On This Count?
Smoke detectors are not considered to be enough of a load to count when adding up your devices.
This usually accumulates between 8 to 10 smoke detectors on your average new house. Even if you’re adding them up on the light circuit you still do not need to include them.
They draw a fraction of an amps therefore no load on the circuit.
It is not OK to run an individual circuit for smoke detectors alone. This would result in the consumer being able to shut them off with the breaker. Fire code states that you cannot do that.
Being on with a light circuit, if you shut up the breaker off then you will lose all the lights associated with that circuit to let you know something is wrong.
This is the whole point of it. In addition smoke detectors must be battery back up.
What Size Breaker Or Fuse Do I Need To Install?
Speaking generally speaking when you’re running a piece of 14/2 or a piece of 14/3 it must be protected by 15 amp breaker or fuse.
If you are using larger loads on 14/2 or 14/3 then you can put them on a time delay do use so it might take longer to pop.
This applies for 20 amp circuit is well you can either have them on a 20 amp breaker or a 20 amp fuse which would be a 12 gauge wire size.
In some cases you can actually run a 30 amp circuit for heavier appliances like a dryer. This is also considered to be a 30 amp fuse for a 30 amp breaker.
In no case should you over a fuse 14 or 12 gauge wire.
More on wire sizes here.
How Many Outlets SHOULD Be Installed On A Circuit?
This is a bit more of a difficult question to answer. How many outlets do you actually run on a circuit.
Well in an ideal world we like to put each room on its own circuit of no more than four or five plugs.
Unfortunately if you were trying to save money this results in more arc fault breaker‘s. At a cost of 80 bucks a piece versus 8 bucks a piece for a regular breaker you can see how this ends up substantially.
We recommend going through your loads that you’re going to be using before you decide. In higher use electrical areas you may want to only run two or three outlets per circuit.
There are actually a whole set of rules for kitchen wiring that you can only run two outlets per circuit as your appliances consume more.
Does This Apply For All Other Circuits?
It actually comes down set of rules, from the kitchen to the basement.
They are all a little different as per our code mentioned before you can only run two 20 amp receptacles on 120 amp circuit in the kitchen area.
You can also only run one device for any high load circuit for example a fridge, microwave, range hood, dishwasher, sump pump, washer machine etc.
You can find out more on home wiring here.
Is It The Same For Commercial Applications ?
The rules for commercial are a little bit different as most commercial buildings have a much higher demand load on their circuits.
Computers, photo copiers, printers or modem’s etc. The all consume a lot more electricity.
We often run 12 gauge only instead of 14 gauge in a commercial setting. This allows us to have 20 amp circuits instead of 15 amp.
We also like to run no more than two outlets per circuit. We try to avoid nuisance tripping as much as possible.
If we are wiring an office building when it comes to how many outlets on a circuit we will usually run one circuit for each device.
As an example we will wire one circuit for computers and also no more than two computers per circuit.
The photocopier would also get a circuit. As well as any other large consuming device.
Lighting for commercial applications can also consumer more. We usually as the individual average is up for each and every light fixture load and then determine the size of the circuit that we need to run.
Outdoor signs especially require a circuit.
You can find out more on the devices, plugs, switches etc that we recommend here.
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