POWER CORDS and GENERATOR CORDS
Generally speaking there are two varieties of portable generator cords. Though their names are often used interchangeably, important distinctions exist between generator cords and power cords. Small and medium-sized portable generators are designed to operate plug-in appliances that can be connected to them with an extension cord. Consider an extension cord designed for this purpose a generator cord. If generator models are large enough in size and wattage, they can also send electricity to an entire house or business office - however this can only be done by employing a transfer switch (also called manual transfer switch and power transfer switch). A transfer switch (which should always be installed by a licensed electrician familiar with building codes in your area) is essentially a safe and secure bridge between generator power and home or building circuits. An extension cord that connects a portable generator to a transfer switch is a power cord.
If you don't have a transfer switch, then you'll be plugging tools and appliances directly into your generator's outlet panel. The 15 and 20-amp wall-style generator outlets are simple to understand, and easy to fit with extension cords right for them. Many small and medium-sized generators are also equipped with a 20 or 30-amp twist-lock outlet [SEE GRAPHIC]; 120/240-volt 30-amp twist-lock outlets are especially common. In all probability, you will have no tool or appliance that attaches straight into a twist-lock outlet, however a shrewd operator can use a twist-lock compatible extension cord to more effectively use overall generator capacity, and power twice as many (or more) small-watt appliances.
Twist-lock cords are available that branch into 4 20-amp outlets at the female end. This provides you with 4 new places to plug in your small appliances, effectively doubling the number of them you can power utilizing your generator's available 15 or 20-amp (wall-style) outlets. The best-equipped generator outlet panels likely possess 4 wall-style outlets. Many models have fewer than 4. So having an extension (generator) cord which is compatible to your generator's 20 or 30-amp twist-lock outlet allows you to utilize the power produced, even if you intend to operate just low-watt appliances.
Here are some additional extension-cord (generator-cord) safety tips from T-REX:
A] Since different tools and appliances require different gauge cords, check the cord's rated capacity in advance of connecting your appliance or beginning your project. In general, the thicker the cord, the greater its diameter, the more capacity it has.
This rule is inverse to the gauge of the wire inside the cord. A 12-gauge wired cord has a greater capacity than a 16-gauge wired cord - something to keep in mind when checking an extension-cord's specifications. When in doubt, you may want to purchase a thicker cord. You can always safely run a low-watt appliance or tool with a larger cord than it requires. You can't safely do the reverse.
B] Avoid using 2-prong cords. 3-prong cords carry a built-in ground which can protect operators from electric shock.
C] Since a generator cord will likely be used outdoors, be certain that it has been manufacturer-rated for outdoor use.
D] Inspect cords regularly, preferably before each use. Avoid using cords which are frayed, cut, cracked, crushed or flattened, or otherwise damaged, or which possess damaged or compromised plugs. Since the result can be severe electric shock, when in doubt, err on the side of caution!
E] An easy way to track the performance of your extension cord is to periodically hand-test its temperature. An extension cord which has been overloaded will be hot to the touch (though not scalding) when it should be cool or lukewarm. If your cord feels hot, then either reduce the load it's connected to (in other words, power smaller or fewer tools and appliances), or switch immediately to a heavier-gauge cord. Remember - overloaded cords are a fire hazard!
F] Avoid covering cords with carpets, rugs, or anything that can hide hazardous damage, or make checking cord temperature difficult or impossible. If a cord is covered, heat can build up to fire-producing levels, even if it hasn't been extended past its capacity.
G] Don't run cords where they may become a danger or tripping hazard - especially not in dimly-lighted areas, indoors or out.
H] Always avoid disconnecting the cord from an outlet by tugging on the cord rather than its plug. This practice can damage the prongs of the plug and affect their safety and integrity.
To reiterate, a generator cord is one which will be used to connect appliances into a generator outlet panel. A power cord connects generator power to an electric transfer switch(or inlet box, often used in conjunction with a transfer switch), which sends it safely into the electrical system or circuits of a business or home. Power cords, unlike most generator cords, usually have identical-rated male and female ends [SEE GRAPHIC].
Two things need to be considered when choosing a power cord. One is the size of your generator outlets; the other, the wattage capacity of your transfer switch. Generator dealers recommend that you purchase a power cord which connects to the largest-amp outlet in the outlet panel of your generator - great advice if your electric transfer switch has the same capacity. So first check the inlet size and rating of your transfer switch - the place on the transfer switch [SEE GRAPHIC] where the power cord will be plugged in. The 5,000-watt transfer switches offered by T-REX, for instance, are designed to be used with a 20-amp twist-lock power cord (#NEMA L14-20R on both ends). Our 7,500-watt transfer switches require 30-amp twist-lock power cords (#NEMA L14-30R on both ends). None of these transfer switches will accept power cords rated at 50 amps, even if your generator outlet panel should sport a 50-amp outlet.
It makes sense, if purchasing a generator and transfer switch together, to choose a transfer switch whose capacity equals that of the largest outlet on your generator outlet panel. And the necessary power cord to connect them of course. The larger the generator outlet, the greater the wattage of the transfer switch it will power. A 50-amp outlet (connected by a 50-amp power cord) can power a 12,500-watt transfer switch. This 12,500-watt transfer switch will power more rooms or circuits in your home or business than a 7,500-watt transfer switch model. If your generator is muscular enough to sport a 50-amp outlet [SEE GRAPHIC AT RIGHT], then having a transfer switch with a 50-amp inlet - and the right power cord to connect your generator outlet to the transfer-switch inlet - allows you to maximize the generator power produced, making it available to power more critical rooms or circuits.