House Wiring Diagram: A Look Inside Your Home

house wiring diagramTo many homeowners, the wiring inside their walls isn’t given even an afterthought unless an outlet or light stops working. The truth is depending on the age of the home and the quality of the initial electrical wiring, a house could be wasting energy and not getting the maximum potential from their electricity. Taking one of these online AutoCAD courses and then obtaining your house wiring diagram copy might give an idea for potential problems and areas that can be improved and upgraded.

In many cases changes to the wiring and internal components of a house should be left to the professionals. That being said, the house wiring diagram can be analyzed and inspected so that common troubleshooting can be performed with ease.

What is a House Wiring Diagram

The house wiring diagram is essentially the internal X-ray of your home. It is a detailed map of the wiring route as well as an indicator of the crucial components along the way. Designers draw up the diagram according to building codes and homeowner specs and electricians follow the blueprint exactly.

The easiest way to read a house wiring diagram is to start at the source, or the main power supply. This is where electricity enters the home from the outside and is distributed throughout each room in the home. From there wires can be followed to where they correspond in the house, including whether wires that cross are connected or not. Specific information along the wire is also shown on the diagram such as if a resistor or capacitor is installed and where the ground is in each location. Specifically on the diagram, outlets and even switch symbols are displayed, as well as light bulb location and type. In many instances, one of these basic Autocad courses can give a person enough of a basic understanding to comprehend the details of the diagrams.

Circuits in House Wiring Diagrams

When reading a house wiring diagram it’s important to understand that the electricity runs in circuits, meaning it completes a full circle. Basically two ‘hot wires’ and a negative wire are the main sources of electricity coming into the breaker from outside power lines. From the breaker the wires take a positive and negative route to the circuit board, aka fuse box. From the box each circuit heads out on it’s own destination whether it be to a dining room, bedroom, bathroom, etc. The wire makes its route branching off into the outlets and light switches of the rooms before returning to the fuse box on the alternate charge of which it left.

For instance, the types of labeling one might come across on a wiring diagram include:

  • Bedroom hot #1 positive to bedroom hot #2 negative
  • Bathroom hot#1 positive to bathroom hot #2 negative
  • Kitchen(a)a hot#1 positive to kitchen(a) hot#2 negative
  • Kitchen(b) hot#1 positive to kitchen(b) hot#2 positive (two positive wires are circuited to acquire a 240 volt connection instead of 120v. This is needed in kitchen ranges, washers, and dryers)

It may sound confusing but a quick run through of this AutoCAD course will give you the basics of how to read the electrical blueprint.

How is a House Wiring Diagram Used to Troubleshoot Problems

In essence, the house wiring diagram is just used to show the DIYer where the wires are. The diagram will show you the type of switches that are supposed to be in a room and all the outlets that are supposed to be connected. If all the outlets on a circuit are ‘dead’ then there could be a problem with the main fuse. On the other hand if only one of the receptacles or light switches on a circuit is without power than the electricity problem can be fixed by replacing one of these faulty devices.

The wiring diagram on the other hand is especially beneficial to an outside electrician. Experts trained in the field can examine these types of common problems based on the wiring map:

  • Overlamping: You are using a higher wattage light bulb than what is designed for a specific room. Doing so can melt the socket and the insulation on the wires and is one of the biggest electrical fire hazards because of arcing.
  • Frayed External Wires: If the lights flicker on windy days then the weatherhead which houses cables from powerlines into the house may have some issues. This is both a nuisance and a danger.
  • Power Overload: Although the dangers aren’t overly excruciating, overloading one outlet with multiple devices is a huge drain on the system. Modern building codes require an outlet at least every 12 feet but some old homes only have one per room. An electrician can reroute wiring and install more receptacles.
  • Bathroom Tripping: It could be possible that the wiring is fine in a bathroom but there are no GFCI outlets in the room. This is incredibly dangerous but grandfathered in to older homes.
  • Overwired Panel: Another way to ease stress from a home’s wiring is by installing a subpanel with extra slots on a fuse box. What happens in many cases is that single pole breakers are replaced with tandem breakers that fit in the same slot but have an extra circuit. This is a code violation with moderate damage potential.

In with most of these instances, the house wiring diagram is the fall back guide to see just how each area in the home was intended to be electrically sourced. If a diagram is not readily available in the home, check with the building authority where the permit was acquired as they usually maintain a copy for their records.

If you’d like to learn more about how to read these diagrams and how they’re created check out the online courses at for AutoCAD, such as this course on learning AutoCAD drawing essentials.