Electrical contractors are responsible for installing, repairing, and maintaining electrical systems in homes and commercial buildings. Due to the differences in skills and costs between home systems and commercial systems, most companies will focus solely on either residential or commercial work. Fortunately, the process of pricing an electrical job is similar no matter what type of building is involved. For those with a basic understanding of construction and electricity, it is fairly easy to price an electrical job and develop an appropriate estimate.
Examine the entire set of project drawings before you begin. Start with the architectural floor plans, as those often will give you the best indication of what each room will be used for. By understanding the intended function of each space, you will also gain a better understanding of the electrical systems for those rooms.
Read any bidding instructions or general specifications before you begin. They will often contain information that could greatly affect your prices. For instance, jobs that will be conducted in phases, or in occupied buildings, often require you to use higher wage rates to make up for time lost due to project interruptions. In an occupied space, you'll often need much more time than you normally would to arrange power outages and to move from room to room as you work. Be sure to check for wage scale and night work requirements, as those often add about 30 per cent to wage levels.
Examine the electrical plans and specifications carefully. Count the material quantities you'll need to provide, including wire, conduit, boxes, receptacles, switches, panels, and other equipment. Send those numbers to your material suppliers and request unit pricing. For residential jobs, you can simply visit home improvement stores to determine the price of materials you'll need. For example, at one national home improvement chain, 12/2 wire for indoor use costs 20p/foot, while another chain sells receptacle boxes starting at around £3 each. To find a comprehensive list of material prices by region, refer to the RS Means Construction Cost Data Book. This resource is updated annually, and is widely used throughout the construction industry for pricing information. Check the company's website or your local library.
Calculate labour costs, based on your average rates, as well as any premiums you determined in Step 2. You'll need to multiply your company's average wage by the estimated number of hours that the project will take. According to the US Bureau of Labor Statistics, the average hourly wage for an electrician as of May 2008 was £15.50, while the median rate was £14.50. You can find average wages for your state at the BLS website, which is listed in the Resources section of this article. If the project requires the work of specialists, like building control technicians or fire alarm installers, you'll need to include a price from companies that can perform this work. Typically, contractors expect electricians to include these items, but because they are so specialised, the work is usually contracted out.
Figure in the cost of permits. Most electrical contractors are expected to secure all electrical permits required for the job. The specifications will tell you whether this is the case on your job or not. Permits are priced based on the electrical load, panel size, or type of equipment that will be used. In some jurisdictions, these costs can run into thousands of dollars for larger jobs. Use your local permit rates to calculate this cost. To learn where you can obtain permits in your area, refer to the "Permit Agencies by State" link found in the Resources section of this article.
Add all of your material, labour, and permit costs together to determine the total estimate of the job. Include overhead, profit, and any miscellaneous expenses.
A good way to test the accuracy of your price is to divide the total estimate by the number of square feet in the project. Compare the cost per square foot to that of similar projects. That will often help you see if you made a major error, such as a scope omission or a math mistake. It will not usually make smaller errors clear, but can help you avoid major bidding disasters.