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APC Data Line Surge Suppression Options


What does APC recommend for correct surge protection of data lines?

Product Line:

APC SurgeArrest
APC ProtectNet


The computer(s), and all other powered equipment, including equipment attached to the computers or to a greater network (through communication lines), should be provided with APC surge suppression using APC Surge or UPS devices*. Devices that might comprise a network that need power protection would be devices such as; computers and monitors; peripherals, such as printers and scanners; and powered network devices, such as routers, hubs, and switches.

The incoming communications service to a network or computer should be provided with the proper ProtectNet surge device given the type of cabling used for the service. Incoming communications services might be provided by a digital T1 line for a larger network, cable modem or DSL broadband service for a home or small business, 56k analog phone line connection for computer internet access or fax communications, single or multiple phone lines provided for a telephone system, or an external antennae for radio communications or for external information gathering for weather equipment.

This configuration scheme will protect all powered devices from damaging surges and over-voltages on the incoming power and will protect against surges and over-voltages over the incoming communications service. However this scheme does not fully protect against power transients on data lines connecting various devices on a greater network, or that connect peripheral devices to individual computers. If network/communication lines run great distances and/or in close proximity to power lines, fluorescent lights, or other sources of EMI (Electro Magnetic Interference), they may be in danger of receiving transient surges across these network/communication lines due to induced voltage on the lines caused by this EMI. For this reason this configuration is suggested for home users or small office networks where cable length and EMI factors may not be a problem

If EMI is causing transient surges, or is a problem only in isolated areas of a network, then this scheme should be used. This scheme will follow all the rules defined in the Good scheme with the addition of ProtectNet devices to isolate certain parts of the network or individual devices from network/communication line transients. The Better scheme might be used to isolate all workstation computers on a network, or in a particular office space, from network/communication line transients by placing the proper ProtectNet device inline with the network/communication line before each workstation computer. This same method could be used to isolate certain racks of network equipment, individual network printers, or other network peripherals from data line transients.

While this method can isolate certain equipment attached to one side of a network/communications cable from transients, it may not protect equipment on the other end of that network/communications cable from damage. When a transient surge is induced onto a network/communications line it has the possibility of damaging equipment on both ends of that line. This scheme is suggested for medium or larger networks that may have concerns with transient surges in particular areas due to EMI or where extra security is needed by isolating network workstations or other important network components from transient surges.


This scheme will provide surge suppression for all power and network/communication line transients on computer equipment or networks. This scheme will follow the defined rules of the Good and Better schemes, but will isolate both ends of all network/communication lines instead of just the ends of particular lines for the isolation of selected equipment. A ProtectNet device should be installed inline on the end of each network/communication line in the configuration of the individual computer or network. This includes cables such as network cables, printer communication cables, network dumb terminal cables, telephone cables, and coax cables.


To provide Superior protection surge suppression, the Panel Mount Surge Suppressor should be used in addition to APC Surge or UPS products and ProtectNet products in accordance with the Best scheme. This Superior scheme will be optimal when it follows the defined rules of the Best scheme, but will also give added surge suppression in the Good and Better schemes. A Panel Mount Surge Suppressor is designed to take the brunt of surges at the power source to your house or building, the electrical service entrance. In larger buildings or industrial environments it can also be used at Branch, Distribution, and Sub panels, or at the electrical service entrance to individual pieces of industrial equipment such as motors and controllers. This device is the first line of defense against larger electrical surges such as the ones caused by lightning strikes and large power grid problems. Any remaining excess voltage will then be attenuated, or shunted, by the individual APC products in the building. A licensed electrician must install the Panel Mount Surge Suppressor.

Make sure the APC product is appropriate for local power events in your area. An APC device that is designed to reduce power surges, spikes, and over-voltages, will not be able to prevent problems caused by low voltage conditions (sags/brownouts, power outages). If frequent power sags and/or outages in your area are a concern, then APC UPS (Uninterruptible Power Supply) products should be used. UPS’s offers, as well as surge suppression, battery back-up power, which can sustain proper power to the electrical load in the event of a power sag or outage.

*APC manufactures large-scale surge protection products, such as the Symmetra and Silcon UPS lines, which will provide proper protection against power line surge events, but do not have coverage under the Equipment Protection Policy.
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