Advanced Fusion System’s (AFS) Ultra-Fast Surge Arrester (UFSA) EMProve® is a grid protection device designed to shunt the induced current resulting from an E1 HEMP or IEMI event away from medium voltage equipment to ground.
During testing at a Nationally Recognized Test Lab (NRTL), the EMProve® shunted more than 97 % of the induced current surge to ground when tested under MIL-STD188-125.

Electrical connections are made to the UFSA by two sets of two NEMA compliant threaded holes.

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Setup and Installation

• The indoor EMProve® (model UFSAXXE1-A, see Fig. 1) is suitable for installation in equipment housings and inside buildings where pollution degree levels are very light to light. 

• The outdoor EMProve® (model UFSAXXE1-B, see Fig. 2) is suitable for all installation locations exposed to the elements, where pollution degree medium to heavy.  

• The EMProve® must not be used as a structural member for any other device or equipment.  

• The EMProve® device is intended to be mounted to the phase conductors and neutral to a solid ground reference, ideally within 1 meter of the asset that is to be protected.

• Due to the fast transient E1 pulse with high di/dt current flowing in the connecting leads, one must expect additional voltages to be developed in those connecting leads.  This will add to the E1 protect levels in Table 1 below, so it is important to have low inductance connecting cables.  A thin wide strap connections are preferred.

• Example:  Assume the inductance of the connecting leads is 250 nH and the 2.5 kA/20 nS current is flowing in that lead, an additional 31 kV to the E1 protect level of the UFSA.

Environmental Specifications

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• Temperature range (storage/operating):  -40°F (-40 °C) to 150 °F (65 °C)   

• Humidity: 5 % to 95 % (noncondensing) 

• Electrical connections are made to the EMProve® by two NEMA compliant threaded holes on each connection flange. Various standard adapters are available at additional cost to facilitate electrical connections.  Custom adapters can be designed and fabricated.

• It is suggested that the bottom conductor of the EMProve® (ground connection) be made with a rigid connection to support the device from below.  However, if impractical, a flexible wire or copper strap of suitable ampacity rating no longer than necessary may be used to make this connection.  

• The top conductor of the EMProve®, phase connection may be made with either a low inductance flexible wire (or strap) of suitable ampacity rating no longer than necessary.