Last year I published an article on home electrical wiring basics. When I looked back at that document, I realized that I have missed several aspects of electrical wiring. This article will complement the previous by expanding the subject matter.
What can you do without professional help?
In Calgary, Canada, the municipal laws allow the home owners to replace devices from the home electrical system. Additionally, the laws also allow home owners to undertake small renovations (without adding or removing new walls or electrical/plumbing fixtures) without any professional help. However, if you decided to add a new electrical outlet, then you must get proper permits from the City Government. Please do not take this as a legal advice. Contact your municipal or other regulatory body for information on allowed modifications to your electrical system.
For the purpose of replacing traditional electrical fixtures with automated (or networked) fixtures with same certification, in municipalities you do not need a permit. It is like just replacing a light switch with another light switch. But if you are unfamiliar with electrical work do not attempt to replace electrical fixtures. Contact a professional electrician for help. I, Sanuja Senanayake or the site sanuja.com will not take any responsibility for any personal injury or property damage.
Not all switches can be replaced
In North America, the home electrical circuits are composed of several types of wires. Each type plays a different role in maintaining the current flow from the main box to the electrical fixtures. These wires are not interchangeable nor can be easily replaced. The type of wires in a typical household can be summarized as:
Hot Wire = Black; carries the electrical potential from the main box to the unit
Common/Neutral Wire = White; carries the return current back to the main box
Ground Wire = Copper (no coloured casing) or Green; used for grounding the circuit for protecting from electrical shock, overloads, lightning, etc.
Returns = usually white but check with a multimeter; also called “Runner(s)” used for light fixtures or such switch circuits.
Not all traditional switches can be converted to automated or remote (“smart”) control switches. Almost all smart switches require constant power. This is achieved using the Common Wire and the Hot Wire. While almost all electrical switches and receptacles will have a Hot Wire, not all of them will have a Common Wire. Especially for light fixtures, I found that some boxes in my house had Runners instead of a Common Wire. This can be a major problem for home automation enthusiasts.
If you have switches without a Common Wire, you have two options. The easiest one is to buy plug-and-play smart switch. For example, you can buy a Z-wave electrical screw-in lamp socket ON/OFF Module (Eg. Everspring AN145). The only downside is that the light switch itself must always be at ON position in order for the smart switch to work. This is however the safest and the cheapest way to fix the Common Wire problem. There are other modules for appliances and equipment that plug into wall receptacles (Eg. Evolve LDM/LPM-15). They are very easy to use and acts like mediator between the unit and the fixture.
The alternate option is to route a Common Wire from a nearby electrical box within the same circuit. The key is the Common Wire must be from the same electrical circuit as the unit that you will be replacing. Use the proper gauge white (cover) wire for the routing. Instead of routing a single wire, I recommend using a cable (lowest possible would be two wire cable) for added durability and protection. You can clip the extra wire on both ends and may be used for future electrical needs.
You can see the patches on the dry wall. I had to create few opening to route the wire within the wall. I also drilled holes on three vertical studs to pass the wire. Therefore I only used metal clips near the second switch to hold the wire to the stud.
Typical Electrical Switch
Following is a diagram of typical electrical writing for a light switch. Electricians may have wired your house differently. Please use due diligence and trace each cable and wire to what it is connecting. I found so many “questionable” circuits.
You can search online for electrical diagrams, but as mention above, make sure your circuit is wired properly. Do not always trust the colour of the wire, but trace each wire.
Very Important Points
Please us common sense when replacing electrical fixtures. If you are replacing an outdoor receptacle, make sure you have adequate weather projection for the new unit. It is also very important to either use an outdoor rated fixture or install an outdoor cover/box. Electricity and water should never mix and inadequate protection from environment may result in electrical fires or major malfunctions in the circuit.
If you are replacing a fixture on a critical circuit, make sure your new smart fixture does not interfere with the normal operations of the circuit. For example, if you are replacing a switch on a circuit that also provides power to your home security system, make sure the switch will not adversely affect the security system’s power.
Another issue is heat. Since all network connected smart switches have antennas to broadcast and receive data, they produce heat. In fact, you can feel the heat on some switches. It is not a problem as long as you provide adequate ventilation. To do that, you should increase the depth and size of the electrical box. I have used 3 unit boxes for 2 switches just to add more room. With additional wires such as Common Wire and Ground Wire running directly to each smart switch, it also provide room for wire management.
When replacing a 60 W (watts) fixture, use a 60 W smart fixture. Do not use a fixture with lower energy rating. Using a lower wattage rated unit may result in electrical fires.
Before closing the electrical boxes with their covers, make sure all the wires are properly installed and nothing is lose. Use insulated tools such as rubber handle screw drivers. Ground yourself to avoid static discharge. Do not leave open electrical boxes or wires for long period (Eg. Overnight) even if the circuit is shut off from power.
If you are unsure of something or uncomfortable with electrical work, please contact a professional.