When choosing emergency power arrangements, first we must decide what we need power for. How much power we need determines the size of the generator. If you only need to power a fridge, some lights and fans, then power needs are low. When you start adding the microwave, the stove, the laundry, the air conditioner, amperage grows pretty quick.
As I think about it, there are several levels of emergency power preparation.
Level 1 - Primitive
Battery power supply for flashlights, phones, radios, etc.
Camping supplies for emergency cooking.
Level 2 - Basic
We all have a generator which already creates electricity - our vehicles. Simple inverters can be purchased for $20-$50 and generate power from the cigarette lighter outlet. These inverters will typically have 1 or 2 outlets, and provide 1-10 amps of power. This is enough power for some lights, phone chargers, TV, laptops, etc. Many basic inverters will also have USB outlets. A fridge will not work on this circuit - most full size fridges require a dedicated 15 amp circuit.
Level 3 - Car Battery Power
In the $100 range, we find inverters that connect directly to a car battery terminal. These can carry more power because they use a larger gauge wire than the cigarette lighter (the larger the wire, the larger the load it can safely carry). At this point you start getting 15-20 amps of power. In a pinch, you can run a fridge or other single appliance. This will save your food, but will run little else at the same time.
A few things to bear in mind when using your vehicle.
- Your vehicle is designed to convert stored energy (fuel) into motion energy. They are not particularly efficient at creating electrical energy.
- Since it has a battery, you can run the engine periodically to charge the battery rather than running the engine full time.
- When using the battery only, there is a risk of running the charge so low the car won't start. I don't have enough experience to know how long the battery lasts or how to determine if the charge is running low. Also, the charge is drawn down based on the imposed load. Larger loads drain the battery faster.
Levels 4-6 - Generator
Up to this point, we've kept our cost down and used mostly equipment we already have and will use periodically. Purchasing a generator is when we cross the line into true "emergency preparation". There are several levels of generator size and connection to the house, depending on budget and plans. It can be done incrementally. Due to their cost, when purchasing a generator, it's important to have a long term goal set. These goals include final total amperage loads, fuel source, portability/permanence.
Generators are designed to convert stored energy into electricity and consequently are much more efficient than using our vehicles.
Since the generator creates exhaust, they typically must be operated outdoors. In emergencies, generators are a high theft item. Heavy chains, locks, etc. will be required to protect your investment.
Part of what makes a generator useful is the ability to power your entire home. This is also what makes them dangerous. Depending on your particular skills, this means either personal research or professional consultation. In short, when there is a power outage, there exists the possibility that a generator plugged into a home could backfeed power into the utility grid and kill a utility employee working to restore power. Any plan to a generator plugged into the house systems needs to include provisions for isolating the house from the utility grid. In theory, turning off the main breaker accomplishes this. Do your own research or consult an electrician on this.
Level 4 - Generator with extension cords
Every generator has multiple outlets. Generators typically have (2) 110 volt duplex circuits (2 duplex means 4 outlets) and (1) 220 volt circuit. The simplest way to use a generator is to plug extension cords into the generator. Use the thickest cords you have - a power cord's ability safely transmit electricity is directly related to thickness of the wires inside the cord. Using too big a wire has no penalty, whereas too small a wire carries severe risk. Undersized cords will overheat and melt the insulation protecting the wire. There is a penalty for long wires too - called voltage drop. That's a homework assignment you can research on your own. In short, don't use cords any longer than you need to.
Level 5 - Generator plugged into the house
Using extension cords, you can plug a generator directly into your house and power any outlet in your home - this is called "backfeeding". This is dangerous and needs caution. Given the low cost of a transfer switch, this level should be skipped. I'm not going to dwell on this other than to say it is a dangerous option. I really only mention this to make sure you don't research and find this option and decide to do it willy-nilly.
Level 6 - Generator with a direct connection to the breaker panel
The final method is the safest method, and once complete, is the simplest method. A transfer switch is inserted into the breaker portion of the system. A transfer switch is designed specifically to protect utility employees working on the line and also designed to insert the generator power into the house supply.
When you do this, remember your generator has a limited capacity. The best way to limit the imposed load is to turn off the breakers. At a minimum, unplug devices from the outlets. Air conditioners are probably not an option for most generators. Air conditioners, stoves, and clothes dryers require 220 power - if you want any of these, make sure you specifically plan for it - not all generators can provide that power.
A neat little guide to figuring out your power needs -
http://g-ecx.images-amazon.com/images/G/01/outdoor-living/detailpages/Whistler-Inverter-Lrg.gif
A brief explanation of backfeeding power into the house -
http://www.tcscooters.com/backfeed.htm
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