Delta Lighting Arrestor - LA301 AC

Delta Lightning Arrestors: Unmatched Protection for Your Electrical Systems

Ensure the safety of your electrical systems with Delta Lightning Arrestors, designed for industrial, commercial, and residential use. Featuring a robust silicon oxide varistor design, these arrestors offer superior surge protection up to 100,000 amps. With response times as fast as 5 nanoseconds, Delta Lightning Arrestors are reliable and efficient. They consume no power during standby and maintain consistent clamping voltage over time. Perfect for photovoltaic systems, they fail open circuit to ensure continued operation.

PV ARRESTORS Delta silicon arrestors comply with all requirements of photovoltaic systems.

Deltas do not draw continuous current.

Deltas consume no power during stand-by.

Delta's clamping voltage does not change with age.

When Deltas fail, they fail open circuit to permit continued operation of PV systems.

Deltas contain no current limiting fuses or resistance. Type

Rated Voltage

Type

Surge Current

Joules

Leads

Enclosure Rating

DimensionsCA 302R

250V Single Phase

3-Wire

60,000 amps

20,000 per pole

18" #12AWG

NEMA 4

4.5" Height, 2.25" DiameterLA 301

125-250V

Single Phase

2-Wire Service

Silicon Oxide Varistor™

100,000 amps

3,000 Joules

per pole

36" #12 THHN

NEMA 4

4.5" Height, 2.25" DiameterLA 302DC

500 VDC

Silicon Oxide Varistor™

60,000 amps

2,000 Joules

per pole

18" #12 AWG

NEMA 4

2.25" Height, 2.25" DiameterLA 302R

125-250V

Single Phase

3-Wire Service

Silicon Oxide Varistor™

100,000 amps

3,000 Joules

per pole

18" #12 THHN

NEMA 4

4.5" Height, 2.25" DiameterLA 303

110/208/250V

Three Phase

3 or 4-Wire Service

Silicon Oxide Varistor™

100,000 amps

3,000 Joules

per pole

36" #12 THHN

NEMA 4

4.5" Height, 2.25" DiameterLA 303G

110/208/250V

Three Phase

5-Wire Service

Silicon Oxide Varistor™

100,000 amps

3,000 Joules

per pole

36" #12 THHN

NEMA 4

4.5" Height, 2.25" DiameterLA 602DC

1100 VDC

Silicon Oxide Varistor™

100,000 amps

3,000 Joules

per pole

36" #12 AWG

NEMA 4

4.5" Height, 2.25" DiameterLA 603

240/480/600VAC

Three Phase

3 or 4-Wire Service

Silicon Oxide Varistor™

100,000 amps

3,000 Joules

per pole

36" #12 THHN

NEMA 4

4.5" Height, 2.25" DiameterLA 603G

240/480/600VAC

Three Phase

5-Wire Service

Silicon Oxide Varistor™

100,000 amps

3,000 Joules

per pole

36" #12 THHN

NEMA 4

4.5" Height, 2.25" DiameterThe Causes of Power Surges

Electrical power surges can range from minor, harmless events to significant occurrences that cause extensive damage.

Small, harmless surges happen almost continuously in electrical systems. A surge is a brief, sudden increase in voltage within an electrical circuit. In electricity, volts are the force that pushes electrical current through the circuit, similar to how pressure pushes water through a pipe. The current, known as amperes or amps, flows through the circuit, creating a magnetic field around the wire. If you could see this field, it would appear as rings around the wire carrying the current. When the current flow stops, like when a refrigerator turns off, the magnetic field collapses, inducing a voltage in the circuit. This voltage is a small surge, which dissipates quickly and is generally harmless.

Larger surges occur when power to a neighborhood or a large area is interrupted. These interruptions can cause significant surges due to the sudden stop of large currents. Power interruptions happen when circuit breakers at power substations trip and then automatically re-close. Breakers trip due to shorts caused by various incidents, such as vehicles hitting poles, trees falling on lines, birds shorting lines, or wind causing lines to touch. These large surges can damage electrical equipment, appliances, and devices.

Even more dangerous surges are caused by lightning. Lightning is a massive surge in the sky. When it strikes or comes near an electrical circuit, it can cause a power surge that damages any connected electrical equipment. Like any electrical current, lightning generates a circular magnetic field around it. Due to its large current, it creates a substantial magnetic field, leading to a significant surge. Even if lightning strikes near a power system, the magnetic field can induce a power surge in nearby electrical systems. A direct lightning strike on a power line causes both a direct surge and a magnetically induced surge.

The largest surges are caused by electromagnetic pulses (EMPs). While any electromagnetic surge can be called an EMP, the term usually refers to surges from atomic explosions. Unlike lightning, which affects a few hundred feet, a nuclear explosion's electromagnetic field can extend for miles. If you are within this range, the EMP can cause severe damage to electrical systems.

HOW ARRESTORS AFFECT SURGES

• Surges consist of two main parts: voltage and the amount of charge. A high voltage surge can harm equipment by breaking down the insulation between circuit elements or between those elements and the ground. The extent of the damage depends on the current from the charge and/or the power source. To protect a circuit, a surge arrestor must conduct enough charge from the surge to reduce the surge voltage to a safe level quickly enough to prevent the insulation from breaking down. All circuits can handle high voltage for a short period. The shorter the duration, the higher the tolerable voltage.

Imagine a fifty thousand volt surge on a two-hundred-forty volt device with a surge arrestor connected in parallel. The surge arrestor will start conducting the charge, removing it from the circuit. As the charge is removed, the surge voltage will decrease. When the charge is nearly zero, the surge voltage will also be nearly zero. If this happens quickly, the device will be protected. The speed at which an arrestor can remove a surge depends on four factors: the voltage magnitude, the charge amount, the speed at which the arrestor starts conducting, and the arrestor's conductivity. If one arrestor has double the conductivity of another, it will handle the surge twice as fast. If two arrestors have the same conductivity but one starts conducting faster, the quicker one will eliminate the surge more rapidly.

CLAMPING VOLTAGE vs. DISCHARGE VOLTAGE

There is no single clamping voltage for any arrestor. The clamping voltage varies based on the current being conducted, the arrestor's internal resistance, its response speed, and the time at which the clamping voltage is measured. When specifying a clamping voltage, the current being clamped should be stated, such as 500 volts at 1000 amps. Without specifying the current, the clamping voltage has no real meaning. Using a negligible current, like one milliamp, any clamping voltage can be achieved, but it offers no protection.

Consider a surge that rises from zero to fifty thousand volts in five nanoseconds, connected to an arrestor that starts conducting at five nanoseconds and clamps the surge to 500 volts in 100 nanoseconds. At any point during the 105 nanoseconds, the clamping (discharge) voltage would differ. Even if the clamping voltage is said to be 500 volts, if measured at twenty-five nanoseconds, it would be above twenty-five thousand volts. An arrestor with a low ultimate clamping voltage might have low conductivity, causing the high voltage to persist.

Delta lightning arrestors and other lightning arrestors are designed to handle these surges effectively, ensuring the safety and longevity of electrical equipment. By understanding how these arrestors work and their impact on surges, users can make informed decisions about protecting their devices. Arrestors with high conductivity (low internal resistance) can quickly conduct surges from the circuit. Those with a high current rating will have high conductivity, allowing them to remove surges faster. The faster a surge is eliminated, the better the equipment is protected. When discussing clamping voltage, always include the current being clamped and the clamping time. Delta lightning arrestors and other lightning arrestors are designed to handle these surges efficiently.