Surge Suppressor Specification recommendations

UL TVSS 1449 Suppression Rating for all 3 modes:

• Hot to Neutral : 330 volts
• Hot to Ground : 330 volts
• Neutral to Ground : 330 volts
• UL 1283 EMI Filter
• UL 497A [ Telco/Modem models ]
• CSA listing

Some surge protectors use 200V (141V RMS) initial clamping lavel in addition to UL 1449 330V surge protection rating.

IEEE 'Standard Test Pulse'

The IEEE 'Standard Test Pulse' (6kv open circuit, 500 ampere maximum current, 20 microsecond pulse length) is intended to represent a 'worst case' exposure from lightning for equipment plugged into an interior AC receptacle. IEEE 500 ampere test pulse could be caused by a 'typical' lightning strike directly on to the power pole outside the building or to the AC service drop.

For 20 mm diameter MOVs, a standard size for high quality protectors, the manufacturer's rating indicate a lifetime of more than 500 surges of IEEE 500 amprere size.

Other details

• Energy Dissipation Minimum 600 Joules [ AC ], 240 Joules [ DC ] for MODEM.
• EMI/RFI Filtering: >50 dB rejection over 100 kHz to 10 Mhz for both Normal (NM) and Common (CM).
• IEEE 587 A Let-through Voltage < 40 Volts [ 6kV ANSI/IEEE C62.41 (587) Category A Ring Wave test ].
• Peak Surge Current @ 8 x 20 us pulse: 40,000 Amps Common Mode.

In addition...

1) Heavy Duty MOV arrays used at BOTH the Line side and the Load side for bi-directional, forward and reverse suppression

2) High Frequency Capacitors used at BOTH the Line side and the Load side

3) Series Blocking Inductor Coils used on BOTH the HOT and the NEUTRAL

4) The Series Blocking Inductor Coils must be positioned AFTER the MOV array and the High Frequency Capacitor arrays on the Line side and BEFORE the MOV array and the High Frequency Capacitor array on the Load side, so that both forward and reverse suppression is provided and so that MOV harmonics are filtered on both the Line side and the Load side

Line -> [HFC] -> [MOV] -> [SBI] <- [MOV] <- [HFC] <- Load

5) The Series Blocking Inductor Coils must be sufficiently sized and properly located so that RFI Emissions and EMI conduction due to saturation at higher loads do not become a problem 6) The suppressor should have a Positive Shutdown Circuit that automatically stops all current flow to the Load in the event of a catastrophic surge hit _or_ in the event of a failed critical suppression component

7) There should be a Diagnostic Circuit that will identify

• a) An Open Ground, Neutral or Hot?
• b) A Hot-Ground or Hot Neutral Reverse?
• c) Verified components of the surge suppressor are functioning?

8) The suppressor manufacturer's warranty should cover Power Surges resulting from lightning, and should be transferrable

9) The surge suppressor's MODEM surge circuit should have NO MORE THAN 50 picofarads of capacitance, and the specifications should so state.

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For more information check Sutton Designs and Panamax web sites.