How do I electrically map my place?

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How do I electrically map my place?

Contributed by: GardenGuy
Submitted: 04-13-2003

Caution: electricity is dangerous and an accident could possibly be fatal. Respect electricity. Be cautious and never rush yourself.

Determining the electrical design of your house will provide you with necessary info on what lights, switches and outlets are associated with which circuit breakers (or fuses). This will also help you in knowing what the electrical limitations are for each of those circuits.

1. it will save you money by saving the electrician time not having to figure this out from scratch on his/her own... in any project now or future.
2. it will show you what amperage rating you have for every circuit
3. it will show you how much power you will be able to use safely in your grow room
4. it will tell you whether you need to move high draw devices (Such as A/C) to different circuits.
5. it will tell you how many circuits are available for your grow room area

Making the Map:

(if you have a friend this will the following process will go smoother and take less time)

1. Draw up a map of the floor plan of your whole house on paper and mark on it every outlet, switch and light fixture (not plugged into an outlet).
2. find where your breaker panel/fuse box is.

3. You can use an outlet tester, a volt meter or even a plug in lamp (or use a radio) if you don't have an outlet tester or volt meter. Outlet testers are easier to use, indicate polarity, ground faults and other electrical problems.

4. note on your map the outlets that are controlled (on/off) by a light switch and mark them on your map (some outlets are split...meaning only one of the two plugs are controlled by the switch ..the other is constant)

5. go to a working outlet and test your tester/meter/lamp/radio

6. turn off one breaker (or pull one fuse) ... not the main for the whole house though

7. go around checking every outlet and light in the house and mark on your maps which one lost power for that particular breaker/fuse.... use your tester/meter/lamp in the outlets.

8. when done checking the house.. turn on that breaker again.

9. repeat steps 6, 7 & 8 until you have all the breaker/fuses, outlets and lights mapped out for your house.

10. Write the general info on your breaker panel in permanent maker (if not there already)... i.e. BKR1 Kitchen Outlets... (later when you decide what one will be the Bkr or Bkrs that go to your grow room I would mark these too, in case of any emergency in the future)


Now that you have your map:

amps x volts = watts
amps = watts/volts

you can make sure that what you have plugged in already on the circuit plus what you intend to plug in with your grow room... won't overload your circuit ...

I usually recommend, in these types of installs, a max of 75% of the rating on the breaker or fuse is ever used for that circuit. Meaning if there is a grow light, or an air conditioner, or pumps etc...on a particular circuit, total them all up.

If they are on a 15amp circuit, for example, I don't like to put more than 11.25 amps total on that circuit ever... so you don't have to ever worry about start up currents being near the level of your breaker tripping.

Editors note:
Most bigger grows need to be in the basement room where the breaker box is located. This keeps the ballast cord runs as short as possible (run cooler, less resistance and line losses).

Smaller grows can be located near 220V plugs (i.e. clothes drier, or even the oven). If you want more power, use existing 220v sources (Such as clothes dryer and oven plugs). Hydroponic stores often sell pre-made timer boards that plug right into a 220v source, with appropriate 110v outlets.

Cabinet and veg room grows can make use of room power outlets - care should be taken to run off different circuits. You can use a grounded extension cord to tap into a circuit in a different room if your main grow room is on one circuit and you need another 15 amp circuit.

Remember, breakers trip thermally when exposed to higher-than-rated current draws. This means an overloaded circuit will take a while to trip the breaker normally this is safe, but older house wiring may not like extra heat.

When you have made any electrical additions, make sure everything is kosher by checking the normal operating temperature of the plugs (with the back of your hand). If a plug has become unreasonably warm or even hot, unplug the device (usually a ballast).

  Last modified: 14:02 - Apr 26, 2003  

faq:1483 "How do I electrically map my place?"