How to Estimate the Amount of Wire Needed to Rewire an Average Home

So far as wiring is concerned, there’s no such thing as an ordinary home. Not only is every single house a different shape and size, but it’s different electrical demands. To have a realistic estimate of the amount of electrical cable your project is going to require, you are going to require a floor plan or a simple wiring diagram. The accuracy of the estimate is dependent upon the accuracy of the floor plan.

Importance of the Wiring Diagram

All the electrical circuits in a typical house originate in the primary panel, which is usually on the ground floor in the point at which the electricity drops in from the electricity lines. An electrical diagram displays information about each circuit, including each light fixture or fixture that’s on it, and — most important for the purposes of estimating — the location of the last device. The distance in the panel to the previous device about determines the amount of cable you require for this circuit. The cable might need to follow a circuitous path to achieve all of the apparatus on it, but for estimate purposes, you can assume it follows the most direct route.

Regarding Wire Gauge

Residential circuits in North America have a voltage of either 120 or 240 V. You want to distinguish these when pellet cable needs, since they require different wire gauges. Moreover, you might need require a different gauge cable to service your 240-V stove than you do for your water heater, and 15-A,120-Metal circuits require a lighter wire gauge than 20-A circuits. When studying your circuit diagram, note the voltage and amperage of each circuit so you can make a record of just how much cable of each gauge you require, but book 240-V installations for a expert electrician.You might opt to follow the advice of some contractors and use 12-gauge cable for all 120-V circuits. This simplifies installation and guarantees that all of your circuits are up to code, though it’s a little more pricey.

Adding It All Up

Now that you’ve got the electrical diagram, relevant distance dimensions of your house and information about the cable gauge required for each circuit, then you have all you will need to make an wiring estimate. Work out the length of each circuit, with your home’s floor plan, and add this length to each of the other lengths for that cable gauge. Add a 10 percent overage to the last summation to account for twists, bends and backtracks. You purchase wire in rolls, so for safety’s sake always round up to the next highest number of rolls. For instance, if your calculations show you require 7 1/4 50-foot rolls, then purchase eight of them.

Specialty Wire Needs

Heavy-gauge 240-V cable is not the only specialty cable you are going to want. If you intend on installing three-way lighting switches, which can be a system whereby two switches function the same lighting fixture or fan, you are going to want 12-gauge three-conductor cable having an extra hot wire. If you plan to install outdoor lighting, then you’re going to want exterior-grade cable that can be buried. Make an extra record for these specialty cables to ensure you have them when you want them. If you aren’t sure which cable type you will need for a specific program, consult with an electrician. You do not want to install a circuit with substandard cable that can not handle the load without straining.

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