Electrical Connections

Surge Protective Devices

All electrical connections should be installed by a qualified (licensed) electrician only. All wiring must comply with the National Electrical Code (NEC) and applicable local codes.

VERIFY THAT ALL POWER CIRCUITS ARE

DE-ENERGIZED AND LOCKED OUT BEFORE MAKING

ELECTRICAL CONNECTIONS.

Voltage Ratings and Power Source Configurations — Before making connections to the unit, verify that the unit model number and nameplate voltage rating are appropriate for connection to the intended power source. See the chart on page 4 for voltage rating applications with typical power source configurations.

Wire Connections — With parallel connection, the size of the wiring to the SPD unit is independent of the protected circuit’s ampacity. NEC Article 285-21(B) requires surge suppressor connecting conductors to be at least #14 copper or #12 aluminum. To reduce the wiring impedance to surge currents, it is recommended that the phase, neutral (if required), and ground conductors are twisted together and routed in the same raceway (conduit). Avoid any sharp bends in the conductors.

Overcurrent Protection — The SPD unit conducts practically no current under normal operation and only conducts very short duration transient surge currents.

NEC Considerations — The following is from the National Electric Code 2008 Edition.

NEC 285.21 Connections

NEC 285.23 Type 1 SPDs. Shall be installed in accordance with 285.35(A) and (B).

(A)Installation. Type 1 SPDs shall be installed as follows:

(1)Type 1 SPDs shall be permitted to be connected to the supply side of the service disconnect as permitted in 230.82(4) or

(2)Type 1 SPDs shall be permitted to be connected in Type 2 locations as specified in 285.24.

(B)At the service. When installed at the services, the grounding conductor of a Type 1 SPD shall be connected to one of the following:

(1)Grounded service conductor

(2)Grounded electrode conductor

(3)Grounding electrode for service

(4)Equipment grounding terminal in the service equipment

Voltage Protection Ratings — To obtain the voltage protection ratings (VPRs), as obtained by Underwriters Laboratory, Incorporated, in accordance with the Standard for Safety, Surge Protective Devices (SPDs), Standard 1449, Third Edition, released (2009), marked on this product, the wire size listed for each product must be utilized to connect the unit to your facilities’ power grid. Connections made with conductors other than the wire size listed may result in different VPRs.

Circuit Ampacity Limitations — Representative samples of these products have been investigated by Underwriters Laboratories, Incorporated to withstand, without exposing live circuits or components at system voltages and fault currents up to 200,000 AIC, as described in the Standard for Safety, Surge Protective Devices (SPDs), Standard 1449, Third Edition, released (2009).

System Grounding and Bonding — The performance and safety of any SPD system is dependent on proper grounding and bonding. Grounding is required for safety. Correct implementation also enhances equipment performance. Incorrect grounding can reduce or impede the SPD’s operation.

All electrical circuits to the SPD must include an equipment- grounding conductor as required by the NEC and local codes.

UNGROUNDED POWER SYSTEMS ARE INHERENTLY UNSTABLE AND CAN PRODUCE EXCESSIVELY HIGH LINE-TO- GROUND VOLTAGES DURING CERTAIN FAULT CONDITIONS. DURING THESE FAULT CONDITIONS ANY ELECTRICAL EQUIPMENT, INCLUDING AN SPD, MAY BE SUBJECTED TO VOLTAGES WHICH EXCEED THEIR DESIGNED RATINGS. THIS INFORMATION IS BEING PROVIDED TO THE USER SO THAT AN INFORMED DECISION CAN BE MADE BEFORE INSTALLING ANY ELECTRICAL EQUIPMENT ON AN UNGROUNDED POWER SYSTEM. CONTACT FACTORY FOR UNGROUNDED APPLICATIONS.

An insulated grounding conductor is required in addition to any metallic raceway, which may be used as a grounding conductor. For parallel-connected SPDs, the grounding conductor should be the same wire size as the associated power conductors.

(continued on page 5)

Installation, Operation and Maintenance Manual

Liebert SPDs SL-22075 Rev 0, 9/2010