Ohm's Law and Electric Heaters

Ohm's Law is the mathematical representation of electricity with regard to Voltage, Current, Resistance and Power (or Watts).  This is required information to know when sizing electric heaters, heating elements, electric water heaters and any high amperage appliances.

Anderson-Bolds Ohms Law Calculator (with 3 phase calculations too)

E = Voltage (Volts)
I  =  Current or Amps
R = Resistance (Ohms)
W = Watts (Power)

Formulas:

W = E x I 
W = I² x R
W = E² / R
I = W / E
I = (W / R)₂
I = E ÷ R 
E = (W x R)₂
E = W / I
E = I x R
R = E² / W
R = W / I²
R = E ÷ I

What is Ohm's Law:

Ohm's Law is made from 3 mathematical equations that shows the relationship between electricvoltage, current and resistance.

What is voltage? An anology would be a huge water tank filled with thousands of gallons of water high on a hill.
The difference between the pressure of water in the tank and the water that comes out of a pipe connected at the bottom leading to a faucet is determined by the size of the pipe and the size of the outlet of the faucet. This difference of pressure between the two can be thought of as potential Voltage.

What is current? An analogy would be the amount of flow determined by the pressure (voltage) of the water thru the pipes leading to a faucet. The term current refers to the quantity, volume or intensity of electrical flow, as opposed to voltage, which refers to the force or "pressure" causing the current flow.

What is resistance? An analogy would be the size of the water pipes and the size of the faucet. The larger the pipe and the faucet (less resistance), the more water that comes out! The smaller the pipe and faucet, (more resistance), the less water that comes out! This can be thought of as resistance to the flow of the water current.
All three of these: voltage, current and resistance directly interact in Ohm's law.
Change any two of them and you effect the third.

Info: Ohm's Law was named after Bavarian mathematician and physicist Georg Ohm.

Ohm's Law can be stated as mathematical equations, all derived from the
same principle.
In the following equations,
V is voltage measured in volts (the size of the water tank),I is current measured in amperes (related to the pressure (Voltage) of water thru the pipes and faucet) and R is resistance measured in ohms as related to the size of the pipes and faucet:

V = I x R  (Voltage = Current multiplied by Resistance)

R = V / I  (Resistance = Voltage divided by Current)

 I = V / R  (Current = Voltage Divided by Resistance)


Ohm's Law defines the relationships between (P) power, (E) voltage, (I) current, and (R) resistance. One ohm is the resistance value through which one volt will maintain a current of one ampere.

( I ) Current is what flows on a wire or conductor like water flowing down a river. Current flows from negative to positive on the surface of a conductor. Current is measured in (A) amperes or amps.

( E ) Voltage is the difference in electrical potential between two points in a circuit. It's the push or pressure behind current flow through a circuit, and is measured in (V) volts.

( R ) Resistance determines how much current will flow through a component. Resistors are used to control voltage and current levels. A very high resistance allows a small amount of current to flow. A very low resistance allows a large amount of current to flow. Resistance is measured in  ohms.

( P ) Power is the amount of current times the voltage level at a given point measured in wattage or watts.

Anderson-Bolds sells Electric Heaters, Watlow, Chromalox, Convectronics, Q'Mark, Process Technology, Danfoss and Brisk Heat.

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216-360-9800

Ohms Law Calculator

TRC High Power GFCI's ~ Ground Fault Circuit Interrupter

Anderson-Bolds and TRC

Avoiding electrical accidents and equipment damage are keys to reducing liability and increasing productivity. Minimum ground fault protection can be incorporated into the main power disconnect device and could be considered adequate for the entire system. However, in such a design, any downstream ground fault could trip the main protective device resulting in a complete substation power outage. The NEC’s purpose, in its own words, is “the practical safeguarding of persons and property…but not necessarily efficient, convenient, or …for good service…” (Article 90.1A, B). In other words, system reliability is left to common sense and good engineering design practices. For this reason ground fault protection of the circuit may be highly desirable and recommended for reliable and continuous operation.

TRC engineers designed the HD-PRO models specifically for high current, rugged environments and these models are field-proven in all kinds of tough applications. The entire HD-PRO family (120V/30A to 600V/80A) is designed to trip within 25 milliseconds after ground fault detection at an adjustable selected trip level of 6, 10 or 30 mA.

ARC WELDING APPLICATIONS

Arc welding is described as using a welding power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point. The process of arc welding is widely used because of its low capital and running costs.

Arc welding can use either direct (DC) or alternating (AC) current as the power source to create the arc. The arc process needs a large amount of current, up to 500A, but at a relatively low arc voltage; 10 to 40V, with a typical high voltage main power supply, and 230 to 400V, that must be reduced. In all manual arc welding operations the main risk is electric shock, most likely from contact with bare live parts of the welding circuit. Appropriate protective clothing and ground fault protection is the first line of defense in the event of an electrical hazard from stray currents. Bad equipment can be replaced in a short time; however, fire and serious injury or death caused by a ground fault could shut down a facility for several days or weeks.

How to avoid electrical shock: Always use a local ground fault circuit interrupter (GFCI) with welding equipment and, prior to use, always test the GFCI for proper operation. Use well-insulated electrode holders and cables. Make sure welding cables are dry and free of grease and oil. Keep welding cables away from power supply cables. Wear dry hole-free gloves, clothing should also be dry. Insulate welder from the ground by using dry insulation such as rubber mat or dry wood. Ground frames of welding units. Never change electrodes with bare hands or wet gloves.

Fortunately, ground fault protection is easy to apply if you understand the basics. Simply put, a ground fault occurs when electrical current finds a bridge to ground via worn insulations, conductive dusts, water or other “soft grounds”, instead of the normal path back to its source. More than 80% of short circuits in equipment are ground faults, and 90% of these events are due to insulation deterioration on wires and cables. In cases where workers accidentally bridge power and ground, current in the mA range can send their heart into ventricular fibrillation.

A GFCI functions by measuring the outgoing amperage to a piece of equipment and comparing it against the return amperage. If a difference (leak) of >5 milliamps occurs (or set higher for certain equipment), the GFCI stops the flow of electricity to protect equipment and workers from potential electrocution.

Avoiding electrical accidents and equipment damage are keys to reducing liability and increasing productivity. Minimum ground fault protection can be incorporated into the main power disconnect device and could be considered adequate for the entire system. In such a design, however, any downstream ground fault could trip the main protective device resulting in a complete substation power outage. The NEC’s purpose, in its own words, is “the practical safeguarding of persons and property…but not necessarily efficient, convenient, or …for good service…” (Article 90.1A, B). In other words, system reliability is left to common sense and good engineering design practices. For this reason ground fault protection of the circuit may be highly desirable and recommended for reliable and continuous operation.

Also, in order to comply with OSHA Regulations’ recent change, “construction-like” work using temporary power arrangements which takes place in the nation’s manufacturing plants, refineries, processing facilities and other locations, must be done with workers using GFCI protected equipment.

Pressure Washer

Industrial pressure washers are powerful tools used for washing buildings, bricks, floors, storefronts, parking lots, dumpsters,

bus fleets, machinery, farm equipment, engines and more. From industrial power plants to disaster clean-up you will find all

types of high end power pressure washers being used for many industrial applications. These machines are sophisticated

and built with more durable pumps and components then the residential units. They are also used in extreme environmental

conditions requiring more power; thereby posing a greater safety risk to individuals if not used properly.

A “Ground Fault” is a dangerous electrical condition where current flows unintentionally

between a live conductor and ground. A severe or fatal electric shock can occur when a user

touches the pressure washer if the machine is ungrounded. This could happen if the power

cord to extension cord connections become wet or a fault exists within the pressure washer’s

sophisticated electrical system. GFCI’s prevent possible electrocution and equipment damage

due to electrical malfunction. Once the GFCI trips, the power is interrupted, stopping the

pressure washer power and making it electrically safe for people and preventing costly

equipment damage.

The 1987 edition of the National Electrical Code requires that pressure washers be protected by ground fault interrupters to

prevent electrocutions. Also, the Underwriters Laboratories revised UL1776 requires the use of GFCI’s for all UL listed

pressure washers effective as of May 6, 2000.

Avoiding electrical accidents and equipment damage are keys to reducing liability and increasing productivity. Guidelines for

electrical safety are:

Always use and test the ground fault circuit interrupter (circuit breaker or outlet) before using a pressure washer.

Always plug a properly grounded pressure washer into a properly grounded receptacle.

Never remove the grounding prong from the pressure washer’s power cord plug or from the extension cord.

Always have a qualified electrician check the pressure washer for electrical problems after it has tripped a circuit

breaker.

HOISTS

Moving large heavy loads is crucial to today's manufacturing and construction industries. Hoists are one of the top

productivity-enhancing tools found almost anywhere goods are regularly moved, worked on and/or mounted into an

assembly. Some hoists use chains, ropes, or cable, but regardless, most use A/C motors. A burnt out motor can be replaced

in a short time, but fire or serious injury or death caused by a ground fault could shut down a facility for several days or

weeks. Fortunately, ground fault protection is easy to apply if you understand the basics.

A ground fault occurs when electrical current finds a bridge to ground via worn insulations,

conductive dusts, water or other “soft grounds” instead of the normal path back to its source.

More than 80% of short circuits in equipment are ground faults, and 90% of these events are

due to insulation deterioration on wires and cables. In cases where workers accidentally bridge

power and ground, current in the mA range can send their hearts into ventricular fibrillation.

A GFCI (Ground Fault Circuit Interrupter) functions by measuring the outgoing amperage to a

piece of equipment and comparing it against the return amperage. If a difference (leak) of > 5

milliamps occurs (or set higher for certain equipment), the GFCI stops the flow of electricity to

protect equipment and workers from potential electrocution.

Avoiding electrical accidents and equipment damage are keys to reducing liability and increasing productivity. Minimum

ground fault protection can be incorporated into the main power disconnect device and could be considered adequate for the

entire system. In such a design, however, any downstream ground fault could trip the main protective device resulting in a

complete substation power outage. The NEC’s purpose, in its own words, is “the practical safeguarding of persons and

property…but not necessarily efficient, convenient, or …for good service…” (Article 90.1A, B). In other words, system

reliability is left to common sense and good engineering design practices. For this reason ground fault protection of the

circuit may be highly desirable and recommended for reliable and continuous operation.

Guidelines for electrical safety are:

Know where the GFCI is located in the hoist power system. If there is not a GFCI installed, have one installed local

to the hoist to confirm you have protection.

Always test the GFCI before using the hoist.

Always have a qualified electrician check the hoist for electrical problems after it has tripped a GFCI.

CONVEYORS

Conveyors are commonly found in factories, industrial facilities, warehouses, distribution centers and in a large number of

manufacturing workplaces. A top productivity-enhancing tool, conveyor systems are used in almost every manufacturing

environment where goods are regularly moved from one location to another. Because of this, conveyor injuries in the U.S.

may cost employers millions of dollars each year; however, with the right processes, design and safety considerations,

employers can reduce cost and liability.

Conveyors are often driven by variable speed electric motors integrated (hardwired) into

complex power systems. As with any electronic equipment they are subject to failure for many

conveyor location to isolate equipment protection and to test the GFCI prior to equipment use.

possible reasons. To protect people who use electrically-powered conveyors, each conveyor

must be equipped with a “Ground Fault Circuit Interrupter” (GFCI) preferably localized at the

GFCI’s prevent possible electrocution and equipment damage due to electrical malfunction.

Once the GFCI trips, the power is interrupted, stopping the conveyor system and making it

electrically safe for people and preventing costly equipment damage.

Ground fault protection is an important consideration for virtually all electrical equipment. A Ground Fault is a dangerous

electrical condition where current flows unintentionally between a live conductor and ground. This could happen if the power

unit or power cables become damaged, wet or a fault exists within the conveyor’ssophisticated electrical system. Avoiding

electrical accidents and equipment damage are keys to reducing liability and increasing productivity.

Guidelines for electrical safety are:

Know where the ground fault circuit interrupter is located in the conveyor power system. If there is not a GFCI

installed, report this to your safety officer.

Always test the ground fault circuit interrupter before using the conveyor.

Always have a qualified electrician check the conveyor for electrical problems after it has tripped a groundfault

circuit interrupter.

HD Pro GFCI's

TRC engineers designed the HD-PRO models specifically for high current, rugged environments and these models are field-proven in all kinds of tough applications. The entire HD-PRO family (120V/30A to 600V/80A) is designed to trip within 25 milliseconds after ground fault detection at an adjustable selected trip level of 6, 10 or 30 mA.

Before the development of the HD-PRO Series, facilities with high current – high voltage equipment or three phase systems employed expensive ground fault breakers at the source of the branch circuit, or went without ground fault protection, leaving personnel and equipment unprotected.

Circuit breakers can withstand high current levels but have short mechanical lives and were not designed for switching duty. Localized ground faults, with circuit breakers, either shut down the whole branch circuit or were overloaded because the available devices were not portable and were often too costly.

The HD-PRO Series utilizes contactors that are fully rated for motor switching demands. In addition to being far less expensive than three phase breakers, the HD-PRO models protect expensive high current – high voltage equipment at the point of use while offering substantial shock protection for personnel.

TRC is an internationally recognized leader in electrical safety products

that protect equipment, prevent electrical fires and protect against electrocution and serious injury from electrical shock.

www.anderson-bolds.com