Could use some electrical advice

We purchased an older home that didn’t have bathroom fans.  We figured it would be straight forward to add a fan to the circuit but it is not and we can’t figure out why. Neither of us know much about electricity.  Currently a wire goes from the outlet to a light that has 5 bulbs and then to a switch.  We thought we could just put the fan between the outlet and the light but it doesn’t work.  We were able to get the fan wired without the light by looking at a diagram someone posted online  but now we can’t figure out how to add the light into it.  Can anyone direct me to an online source that explains how to wire this type of circuit  or give me a quick explanation. I’d really like to understand it so a source that explains it would be great.


I’ve attached two rough pictures of the way it was and what we are trying to do.


Thanks!

You have not shown where the power is coming into this diagram, there should be black and white wires leading back to the panel somewhere in there. It doesnt really matter for just tying into the existing light circuit, but if you wanted another switch it might be more relevant.

Basically the hot wire (black) will bring power from the breaker to a switch, and from there it goes to the load and makes a complete circuit back to the breaker panel on the neutral (white) wire. An outlet is always energized (unless it is a switched outlet, which could be possible if this wiring was done a long time ago). A dedicated outlet will have wires routed back to a breaker as well. These days code would have them on separate circuits, I think, and that outlet would have to be GFCI if it was in a bathroom (this is a cheap and easy upgrade by just putting in a new GFCI receptacle, and it would be a good idea to do that while you are in there). Dropping a hair dryer into the tub used to be fatal, but for 30 bucks it doesnt have to be.

So; If you want to put the fan into the light circuit, then you would just splice it into the light fixture wiring. Inside the fixture there should be two wire nuts, one with the black wires, one with the white. Just splice in the wires that lead to your fan; black with black and white with white, and it will turn on when the lights go on. There should also be a green or bare copper wire in there that is the ground. Connect that as well. If there is no ground, I would suggest you get an electrician to update your house's wiring, as it needs it.

Sometimes in older homes, they brought the power into the light and just dropped a "switch leg" down to the switch. Which is how they wired your bathroom. The power comes from the panel into the receptacle outlet, power then goes up to the light, and back down to the switch. The circuit to power the light is controlled by the switch.  If you want the fan and the light to come on at the same time using a single switch, or if you want to install a separate switch and control them separately, you will wire it differently.

There are two "legs" in a typical home electrical system: the hot leg (typically the black wire) and the neutral leg (typically the white wire). Both legs come from the electrical panel into the outlet. they both travel from the outlet up to the light fixture. The white one is attached to the light and the black one goes down to the switch. I do not know which wire on the switch leg they tied to the black wire coming from the outlet. It really doesn't matter, they both become "hot legs" that carry power to the light fixture.

Here is what you need to do to make one switch control the light and the fan simultaneously:
1. Identify the two legs coming from the outlet up to the light box.
2, Take two pieces of white wire and wire nut them to the white (neutral) leg. Tie one of them to the light fixture and the other one to the fan.
3. Take the black wire from the outlet and wire nut it to one of the two wires going to the switch.
4, take two pieces of black wire and wire nut them to the other wire coming from the switch. Tie one to the other lead on the light fixture and one to the other lead on the fan.
One switch will turn on both devices.

If you want to install a separate switch for the fan, repeat steps 1 and 2 from the above process. then:
3. Take two lengths of wire (both lengths have a black and a white wire) Attach each one to a switch. Black wire on one pole, white wire on the other pole. These are your "switch legs".
4. Take the black wire coming from the outlet and wire nut the two black wires in the switch legs to it.
5. Take one of the white switch legs wires to the open lead on the light and the other white switch leg wire to the open lead on the fan.
Each switch will operate a single device. one switch will operate the light, the other operates the fan.

If you want a drawing, let me know. I can put one together for you.

Thank you both. This was very helpful.

Some questions to ask yourself

Is the plug only on when the light is on?  
Do you want the fan to only and always be on when the lights are on?
Do you want it done to code (which requires you need to know your local code)?  (yes if you plan to sell the house in the future or if you have insurance).

The first step is to get a tester.  The hardware store should have this and it's really cheap.  The hot wire should be black, but as I've discovered in this house, it isn't.  Sometimes it's white.  Sometimes it's red.  All a black wire means is that the wire has a black coating on it.  (like how a right turn signal blinking on a car doesn't mean the drive is going to turn right soon, it just means they have their right turn signal on).

The actual doing isn't too hard, but the thinking it through is the bit I always get blustered about.  I tend to get someone who knows electrical work, buy them some beer, and get them to talk me through while I do the work.

Mary, in my opinion you ought to think about getting an electrician in.
In Australia its illegal to do you own wiring.
I actually do my own, but I have burnt out the side of my thumb, blown fuse boxes to bits and still managed to stay alive.
I have studied all sorts of circuits and still take care.
We have 240V systems here.
If you have never do electrical work it may be harder than you think.
Just saying!!

Be a careful. Turn off the breaker before working on any wires. I’m visiting a new 1 year old house in Germany and there are no bathroom fans strangely. And I’m not aware of any fresh air ventilation either. I’m hoping to bump into a builder who speaks enough English to explain it to me. The houses all are made of blocks and tile. I don’t think they would pass the insulation codes in America. I think maybe they don’t have enough lumber here to build with it.

Joshua,

I think I could use a diagram. My husband seems to have it working, but it seems different than what you said somehow.  

The person who wired our house seemed to randomly decide what color of wires to use so the colors don’t seem to mean anything.  We had an electrician rewire our light switches in our hall a couple of years ago because they would turn each other off and he mentioned the colors didn’t match up which appears to be true in our bathroom as well which makes things harder.  


For others who have asked, we do want both the light and fan to come on at the same time and it is wired like Joshua suggested.  It comes from the breaker to the outlet which is GFCI, up to the light, and down to the switch.  It appears to be the only thing on that circuit and it does have a ground. I do have a multimeter but it’s been soooo many years since I’ve used one that I can’t remember what any of it means. I have to admit that the electricity portion of my physics class was the most confusing for me and electricity scares me so I probably didn’t put in as much effort as I should have to learn it since , at the time, I didn’t want anything to do with it. Maybe it is time to take a trip to the library because I really do like to thoroughly understand what I am doing before I do it.

All of this info has been so helpful.  Thank you all for your responses.

Mary, please post a photo of your multi-meter. I can probably explain how to use it for this operation. I will make a drawing for you later today.

Thank you Joshua. I will try to post some pictures of my multimeter. I can’t seem to figure out how in this reply

Forgive me if the following sounds like I am talking down to anyone. I have been in the building trades most of my life, and I currently work in the Building code enforcement arena. So I often forget that I may be talking to people who don't understand the technical terms, or don't have the basic knowledge. So I am going to bring this down to basic beginner level.

Let's start with power to your house. Most houses are call single-pjhase systems. There are two hot legs feeding the panel board (that's the technical term for circuit breaker panel or fuse box), one Neutral leg, and a system ground. In the photo below, I have a photo of the panel board that just powers my shop receptacles (most people call them outlets or plugs), and my shop equipment. The three wires marked with blue arrows are the feeders. These bring power and a neutral leg into the panel board. The black ones are the hot legs, the one with white tape on it is the neutral. The black ones are in the screw lugs that serve the circuit breakers, the white one is connected to a lug at the base of a separate rail. This is where all the neutral wires get tied.
The green wire (red arrow) is tied to the ground rail (also a red arrow). Each circuit breaker is served by one hot leg, and will have a hot wire coming out of it. These can be any color, but standard colors are black, red, or blue. Note that some of my circuit breakers (green arrows) are doubled with a tie bar. These serve 240 Volt equipment that requires two hot legs to run properly. From here on, I will refer to wires as either Hot leg, neutral leg, or ground wire. I will dispense with using color identifiers. The basic rule of electrical circuitry is that power comes down the hot leg to the device, and returns on the neutral leg to the power source and/or ground. This makes a complete circuit.

Test equipment is NOT optional when doing electrical work. Let's face it, electricity is basically black magic and can maim or kill you in a most unpleasant way that will hurt like the Dickens all the time it is happening. So, if doing your own electrical work is something you are not comfortable with, STOP right now and call someone who is. The first photo is a simple circuit tester. It tells you whether there is voltage between the two probes. It has two lights, one for 120 Volts, another for 240 volts. touch the two probes to different objects (like the bare ends of wires) and see if a light lites up. The second picture is called a multi-meter. It can check for all sorts of stuff, which we won't get into right now, we will focus on checking for voltage. I have set the selector switch to the Voltage section for 200 volts. This section has two options, 200 and 500. This is because most wiring systems are either 120/240 or 240/480 volts. I am going to work inside the 200 volt range for the lighting/bathroom fan circuit. Note that when the two probes are not connected to anything, the voltage meter reads zero volts.

Now let's look at a typical GFCI receptacle. There are three ports in this receptacle. One that is vertical (hot leg), one shaped like a sideways T (neutral), and one that is partially rounded (ground).

Testing to find the hot leg: There should be voltage between the hot leg and the neutral leg, and between the hot leg and the ground. There should be zero voltage between the neutral leg and the ground.
First photo is testing between hot and ground. Second photo is testing between hot and neutral. third photo is testing between neutral and ground. So if you are looking at three wires in a box in the ceiling, two of them are clad in some colored coating and the thrid one is bare copper, you need to figure out which one is hot, which is neutral, and which is ground. using the circuit tester or the multi-meter you can touch the probes to the ends of the wires and figure it out.

For those of you wondering why there is only 102 volts between the hot side of the receptacle and the ground, it is because I failed to make good contact with the ground inside the receptacle, and I didn't have my glasses on when I took the picture.....)

Mary, here is the drawing of how you should wire the light and fan to come on with a single switch. If the light and/or fan have color coded lead wires, the white one should get the neutral leg, the black one should get the hot leg. DO NOT take the neutral wire through the switch!!! That can cause problems........
Remember to attach a ground wire to both the light fixture and the fan.

Thank you