Electrical Info

Electrical Info Center

This portion of the site is dedicated to providing you with additional and hopefully helpful information about electricity, electrical terms and electrical scenarios. With an absence of knowledge on any given subject, it can seem quite a confusing mystery. The different subjects shown below are some of the things that may or may not be unknown or complex to you, but we hope to provide some kind of assistance in giving you more understanding and control over your electrical concerns and projects.

If you have any additional questions or thoughts, don't hesitate to contact us.


Electricity is a flow or movement of electrons from one point to another. It’s that simple. We use this flow to operate motors, light up factories and whatever else you care to imagine. To pull this off, we need to set up a path for these electrons to flow on. We also need some form of a power source or pump to get the electrons going. Lastly, we need something to operate e.g. a light bulb.

The path from a power source through, let's say, a light bulb, and back to the power source is a loop or circuit. All of the systems we deal with are set-up in this way. The electrons in the circuit are pumped round and round by the power source. When the electrons go through the light bulb they perform their magic and make the light bulb light. That’s all there is to it.

Now for some terms. Some of these terms may seem fancy, but they are really easy to understand. Most of these words were named after the people who had some hand in the discovery.


Voltage is the push or pressure which causes electrons to flow. The amount of pressure is expressed in volts e.g. 120 volts, 240 volts, etc. The higher the voltage, the more the push or pressure. The presence of voltage does not necessarily mean that electrons will flow. Take for instance the outlet on the wall. If nothing is plugged in, there is nowhere for electrons to flow yet voltage is present. It is similar to pushing against the back of your car with the parking brake on. The car doesn’t move, but you were pushing against it.


Current is the flow of electrons in a circuit. The flow of electrons is very similar to other types of flows you run into on a day to day basis: water flowing down a stream; people walking through a hallway; cars flowing down a freeway. In each case there is a path being followed and something going along the path. It really is that simple.


Amperage is the measure of current in a circuit. It is the number of electrons which pass through a circuit during a specific period of time. We use the shortened version amps as in “12 amps” when we are talking about how much current is flowing. The greater the amperage in a circuit, the greater number of electrons are flowing at that time. Consider cars traveling on a freeway. The number of cars passing a particular overpass in one minute would be the amount of flow.

Experts in traffic control likely have a term like CPM (cars per minute) to simplify their discussions. The statement, “Hey Bob, we could increase the CPM on that interstate by adding a lane,” would be a very quick way for the experts to communicate about the subject. The same is true for the term amp. Electricians use the term daily to discuss electron flow. If you say, “Hey Bill, that toaster circuit needs to flow 12 amps,” this communicates to Bill how much flow he will need to allow for, and he can then design the circuit correctly.

How many amps is a lot? Well, to give you some perspective, each light bulb in your house flows a bit less than 1 amp while the common toaster or portable heater flows about 12 amps. The electrical equipment that brings power into most houses is rated to flow 100 to 200 amps. Industrial plants can require considerably more amps, sometimes into the thousands of amps.


Resistance is the opposition to current flow. Just as the name implies, resistance resists current flow. The greater the resistance, the less current will flow. If there is a wreck on the freeway and several lanes are closed, much fewer cars will be able to pass through the bottleneck.


The ohm is the unit of measurement for resistance. The number of ohms tells you how much resistance exists in the circuit. The greater the ohms, the greater the resistance.


A load is anything that requires electricity to operate. Motors, light bulbs, toasters, computers, and blow dryers are all loads. They use the flow of electrons to perform their designed task. The reason they are called loads is because the power source must push the electrons through them, and this requires a certain amount of effort. Large loads require the power source to work harder than small loads.


A circuit is the path through which electrons flow. A circuit always starts and ends at a power source. The electrons are pushed out of the power source, driven through any load and then retrieved by the power source.

Ohm's Law

Ohms Law is a very handy formula that you can use to find out what’s going on in an electrical circuit. The three components of the law are Voltage, Resistance and Current. If you know any two of these components you can determine the other by simple math. An easy way to remember the formula is “V” (voltage) is always on top while “R” (resistance in ohms) and “I” (current in amperage) are drawn below.

The rule to using the formula is simple. If voltage and one of the bottom elements are known, divide the voltage by the bottom element to find the missing value. If the two bottom values are known, multiply the bottom values to find the voltage.

Here are some examples that may help to illustrate the use:

If the voltage(V) is 120 volts and the resistance(R) is 100 Ohms, what is the current(I)?
120 volts(V) / 100 ohms(R) = 1.2 amps(I)
If the current is 12 amps(I) and the resistance is 10 Ohms(R), what is the voltage(V)?
12 amps(I) x 10 ohms(R) = 120 volts(V)


PMI is an acronym for Preventive Maintenance Inspection. The term is used generally in all manner of industry to describe the activity of inspecting equipment and/or systems for abnormal conditions or wear which should be addressed to keep the system up to snuff.

Electrical PMI focuses on electrical systems and apparatus. These systems have unique characteristics and require specialized inspections by technicians trained in what to look for.

The specific areas addressed are:


The first step of any PMI would be a basic cleaning of the equipment. The intent is to remove accumulations of dirt and dust from insulators, vents, breaker and switch surfaces, etc. Such accumulations are not only unsightly but have been known to contribute to catastrophic equipment failure.

Visual Inspection

Some potential electrical problems can be avoided by simply visually inspecting the equipment and systems. We look for anything out of the ordinary like discoloration of conductors and components; corrosion; pinched or otherwise damaged wires and cables; missing covers, supports, brackets, etc. Essentially, we are looking for anything out of the ordinary which could cause a problem.


Bolts and nuts can loosen over time, and loose connections cause excessive heating which can destroy electrical equipment. As a part of any PMI, we check each bolted connection for proper torque and bring it up to spec as needed. This includes bolted buss junctions, breaker to buss connections and cable to breaker connections.

Generic Torque Table

Bolt Size (measured by bolt diameter)Torque ft lbs
Grade 2Grade 5Grade 8Caps Screws


Insulation Testing

After the cleaning, visual inspection and torquing, we will then test the conductors for potential faults. This is done using a megohmeter which applies 500 or 1000 volts across the conductor being tested to check for leakage current where it should not exist. How and where to test can be pretty involved and should be left to an electrician with the appropriate training.

Infrared Inspection

By using infrared scanning equipment, we can locate potential trouble spots which would not be visible to the naked eye. The testing is done while the facility is under load, meaning in full operation. Where an abnormality is detected, the circuit in question will be amp checked to narrow down the cause. Areas that need to be addressed are noted with the recommended corrective action and urgency.

Cold starting lamps - though not only possible but done all the time – is pretty harsh on the electrodes at each end of the lamp and will lead to a shortened lamp life. It is far gentler to start a hot lamp. This being the case, several types of ballasts are available that can pre-heat the lamp ends to provide a gentler start-up, thereby extending the life of the lamps. These ballasts are generally more expensive and may require a bit of additional wiring in the fixture to implement, but, where frequent starting of lamps is likely, they may be well worth the added expense.

Infrared Inspection FAQ

A. No. Infrared Inspections can only detect overheating; other types of defects may not show up. Fortunately, these are not common and can likely be discovered and corrected through an inspection.

A. Infrared Inspections are like a checkup at the doctor or dentist. They don’t always find problems, but when they do, they can save a lot of cost and headache by making repairs before a failure. Electrical systems that are lightly loaded and seldom modified are usually less prone to trouble and can often extend the time between examinations. When you have a facility with large electrical demands or lots of additions or relocations, then a scan might be recommended fairly often.

Click here to view an example Infared Inspection Report

Circuit Breaker Trip Testing

This is a specialized test of specific circuit-breakers in the system. It is a test of the trip mechanisms by using low-voltage high current test equipment. By passing a known amount of current through a breaker and timing the trip response it can be determined if the trip mechanism is functioning within specifications. This test equipment is pretty specialized, so we use outside contractors for this service. To perform this service the system will need to be shut-down and the testing company will need to provide a portable generator for testing power.

Ground Fault Testing

This is a specialized test of ground fault detectors and trip units in switchboards. The testing is similar to circuit breaker trip tests, but addresses ground faults which are a much lower magnitude of current. Again, specialized equipment is required, so we use an outside contractor.


Lighting an Office

The lighting of an office, factory floor or warehouse can make coming to work a pleasure or a disheartening experience. Poor fixture placement and wrong fixture types are just some of the ways lighting can make a space feel small and uninviting. Selecting the right fixtures and positioning them wisely can make a place feel large and comfortable.

Lighting Tall Spaces

When lighting tall spaces, and this is just from personal experience, it seems people commonly select fixtures with reflectors intended to focus the light at the work surface. They figure the more lumens at the surface the better.

What often results is a cave effect. All lighting is directed down and virtually no light goes up. Though the room may have a 14’ ceiling, it feels like 8'. I always elect to get some light up toward the ceiling. Even though this does reduce the lighting at the work plane a bit, the increased sense of space seems to make people a bit more comfortable. It's a lot like using a flashlight in a dark room versus an omni directional lantern. The flashlight is more focused, but the lanterns wide beam-spread opens up the space.

Lamp Color

Colors of lamps vary widely. Some are intended to make a space feel cool while others give a warmer glow. The color of a lamp is expressed in degrees Kelvin: 3,000 degrees being fairly warm while 4000 and up gets cooler. The lamp color directly affects the coloration of the objects being lit.

CRI stands for color rendering index. This is the measure of how well a particular lamp will reproduce the colors in the objects being lit. This value is important where accurate coloration is important as in inspection areas, displays, etc.

Low Voltage Lighting

Low voltage (LV) lighting is really any lighting that operates down in the below-25-volt range. The key benefit to LV is that the lamp can be made smaller and thereby produce a more controlled and focused beam. Most commonly used as accent lighting, LV can also be used for ambient lighting, but some may object to the look; looks a lot like aiming spot-lights from the ceiling to the floor, but it can be an interesting look especially with light colored walls and hardwood floors. In such a space, the room will take on a warm look from the color of the floor.

Wiring LV lighting requires more careful consideration of wire size where the low-voltage wiring will be run any appreciable distance. This can be ignored where the fixtures contain integral transformation.

Fluorescent Ballasts

The ballast in a fluorescent fixture controls the electrical current through the lamp. It is a required component of fluorescent lighting. For proper operation, the ballast ratings must match the lamps and a mismatch will damage the lamp, ballast or both.

Electronic vs. magnetic: Magnetic ballasts have been around from the beginning. These ballasts contain transformers which control the energy through the lamps. As technology improved so did the magnetic ballast. Better material and techniques resulted in more and more efficient designs. But, then came the “electronics” which are able to more precisely control the lamps at a much greater efficiency. They also run the lamps at a much higher frequency than the 60-cycles-per-second that the magnetics use. This has the added benefit of reducing flicker – a common complaint with fluorescent lighting.

Starting a fluorescent lamp: This is accomplished by applying enough voltage across the ends of the lamp to create an arc of current through the tube. Once that arc is struck, conditions in the lamp change making continual arcing much easier. (By the way, this is where the ballast comes into play, controlling the flow. Without it, the current flow would run-away and something would fail in short order.) Getting that initial arc can require quite an elevated voltage. How elevated depends on the temperature of the lamp in general and the electrodes in each end in particular. In other words, heat up the ends and an arc is much easier to create.

Cold starting lamps - though not only possible but done all the time – is pretty harsh on the electrodes at each end of the lamp and will lead to a shortened lamp life. It is far more gentle to start a hot lamp. This being the case, several types of ballasts are available that can pre-heat the lamp ends to provide a more gentle start-up, thereby extending the life of the lamps. These ballasts are generally more expensive and may require a bit of additional wiring in the fixture to implement, but, where frequent starting of lamps is likely, they may be well worth the added expense.

Starting types:

Instant start; This is the most common and inexpensive ballast type available. It performs no preheat of the electrodes, just pure force is used to strike the arc. These ballasts are most appropriate where lights will remain on for many hours at a time (very little switching).

Rapid Start; This type of ballast preheats the electrodes at each end of the lamp, and when the temperature reaches a suitable level the applied voltage will strike an arc. This is much easier on the lamps than instant starting but the lamp heating remains on whenever the fixture is operating. This consumes additional energy and is pretty much useless for the operation of the fixture. These ballasts would be a good choice in areas with lots of switching anticipated.

Program start; This is a newer – and more expensive – ballast type that provides the electrode pre-heat and then discontinuous heating when the arc is struck. The ultimate in performance, this ballast could be used anywhere, but sometimes initial cost will put it out of contention.

Low Bay

Discharge lighting used when mounting heights are relatively low. They usually include a bottom diffuser to spread the light over a larger area.

High Bay

Discharge lighting used when mounting heights are relatively high. They usually throw a rather narrow beam of light but from the high mounting height the resulting light at the work plane is not an issue.

Voltage Drop

This article is written for the end-user of electrical equipment – it is not a technical paper on the subject. My intent is to provide a rudimentary explanation of voltage drop and how it may affect one's operations in terms that laymen can understand. I believe that, given an interest and a willingness to learn, anyone can learn anything, and electricity and its related phenomena are no exception. There are a lot of technical aspects to this subject, which if included in this article may make me look really smart, but would defeat the purpose. So bear with me. If you are a technical wonk and find this piece to be overly simplistic – it is!

Voltage drop is the reduction of voltage between a source and a load. What does this mean? All it means is that that 120 volt power from your circuit breaker panel (source) is something less than 120 volts when it reaches your equipment or appliances (load). How much less is what to be concerned with. A couple of volts is no big deal, but when it starts dropping several volts or more, problems can arise.

Equipment or appliances may not operate as expected; computers may mysteriously re-boot; lights may flicker or have a hard time starting all together. All of these ills can be avoided by proper wiring design. It’s not rocket-science, but it does take an understanding of the cause and effect of voltage drop.

Voltage drop occurs whenever electrical current passes through a wire. The amount of electrical current, size of wire and length, is what determines the amount of drop. Changing any of these factors will change the voltage drop in the circuit. Ideally, we want to have full voltage at all outlets and equipment, but this is not really possible, so what we really go for is limiting the drop to less than 3% of the voltage (3% is the limit recommended by the electrical code).

When distances become great, voltage drop may become an issue. Long wire runs are a principle cause of voltage drop. The longer the run, the greater the drop. When you need that new outlet in the back of the warehouse a few hundred feet away, you should ask yourself, “What will the voltage drop be?”. Unfortunately, not all electricians consider voltage drop when installing new wiring, they just use the standard wire gauge and hope for the best or don’t consider it at all. This is not a condemnation of all electricians. As a matter of fact, there are an awful lot of good ones out there - and they will do it right - but it is always a good idea to ask the question, “How about voltage-drop?”

A large amount of current is another basic factor in voltage drop. The greater the current, the greater the drop. Again, the solution is larger wire. The key to avoiding problems is finding a suitable size wire that keeps the drop to a minimum while not breaking the bank. Stay within the 3% limit and you should be fine.

So what do you gain by understanding voltage drop? Maybe nothing at all, but then again, maybe a lot. Computers randomly rebooting, blowing power supplies, etc? Machines or appliances performing at less than par? Fuses blowing or breakers tripping from time to time? All of these, and more, can be symptoms of low voltage. If the cause of the problem is not immediately apparent, have it checked out. It might not be an equipment problem, but a voltage problem.

Service Installations

Installing new electrical services is a coordinated effort between three distinct organizations: The Department of Building and Safety, the Utility company and the electrical contractor. We would install the system, the Department of Building and Safety inspects and OKs the installation and the Utility makes the connection.

The specific services we provide are:

  • 1. We contact the Utility and obtain a meter spot. (The meter spot is the physical location on the premises where the Utility wants the equipment placed).
  • 2. We obtain permits, install the new service and request inspection from both Building & Safety and the Utility.
  • 3. Building & Safety inspects the installation and, if OKed, notifies the Utility of the approval.
  • 4. The Utility does its own inspection and then awaits a written approval from Building and Safety.

Choosing an Electrical Contractor

Most business consumers are incredibly savvy when it comes to making purchasing decisions for their company. They routinely research, shop and select the most bang-for-the-buck. They consider brand, quality, cost and other factors and then make a decision based on the best fit for their need. When this close scrutiny is skipped either for lack of time or interest, the doors open wide to big mistakes.

Say you are looking for a new computer system for the office and are simply too busy to mess with it or have no idea what such a system would entail. You call up ABC computer (from the phone book), tell them what you need and they “set you up”. Now, if you are very, very lucky, you get what you asked for and at a good value. Unfortunately, more times than not, it will miss the mark.

The system will either be slightly off or completely wrong for your operations. You may waste a great deal of time trying to get it to work the way you want and, worse, eventually have to scrap the whole thing and start over. This is not some wild exaggeration. It happens all the time. Consumers ask for a product and get something different than what they asked for.

Successful shopping requires an educated consumer and there is no way around this.

You have to know what you want and be able to communicate your needs. To simply ask for a toaster can result in literally hundreds of varied results. You have to be much more specific in order to receive what you want.

Shopping for electrical service, or any service for that matter, requires a slightly different approach by the consumer as you are not really buying a tangible product but a service. Sure, you still need to be educated and know what you want, but selecting a contractor is more like hiring an employee than buying a machine.

It would be comparable to hiring of a new bookkeeper. You’d want someone you could deal with, who can understand your system of bookkeeping, who is reliable and doesn’t make mistakes. To just hire a bookkeeper for one week’s worth of work and then solicit for new bookkeepers each week thereafter would be a mess. Each new hire would spend most of their time trying to figure out your books and only get to the real work at week’s end.

The same holds true for contractors. You’d want someone that you can deal with.

You’d want someone who understands your electrical system and can implement your requests with ease. You’d want someone who anticipates problems before they arise and proposes good solutions. You’d want someone who shows up when needed and gets the work done fast and charges a reasonable fee. Last but not least, you’d want loyalty.

Just a note from a contactor’s perspective. The vast majority of our customers are very loyal and they call us for all their service. In exchange for such loyalty we will move mountains for them. If they have an emergency or some unexpected demand, we do whatever is required to get them serviced. We consider ourselves to be a part of the team, not some opponent that may take advantage of a bad situation. It’s just like having a trusted manager in your employ.

Some disaster unfolds at 2:00am and that manager doesn’t hesitate to come in and take charge to get the matter resolved. But, how about the employee that you call @ 2:00am who says “I’m Sleeping” or “Would I get overtime?” He probably will not be advancing any time soon.

Finding a good contractor is not only possible, but vital to a flourishing business. The more electrical work you routinely require, the more important the choice.

So what do you do?

  1. Check all the rudimentary requirements like licensing and insurance. This will sort a lot of wheat from the chaff.
  2. Get references. Any contractor worth his salt should be able to refer you to a list of satisfied customers in similar businesses to yourself. Actually call some of these people. Don’t just buy the contractors insistence that “Everybody knows I’m the best.”
  3. Call them in and meet them. Just like interviewing a new employee you can tell a lot from talking with them. Do they look and act professional? Do they seem to know their business?
  4. Try them out. Maybe you need an outlet or light added or a machine is acting up. Have them perform the service and see if you like it.

Why Choose Southwest?

  • Full Service Company
  • Honest, Fair Pricing
  • Quality Work Every Time
  • Free Estimates Available
  • Available 24/7 For Current Customers
  • 40+ Years of Experience

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