5.3. ERMU SR 12-11-2007 - Laserfiche WebLink

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Visible Disconnect - A disconnecting device shall be installed to electrically isolate the Distribution System from the Customer Genertor. The only exception for the installation of a visible disconnect is if the Customer Generator is interconnected via a mechanically interlocked open transfer switch and installed per the NEC (702.6) "so as to rp event the inadvertent interconnection of normal and alternate sources of supply in ~ operation of the transfer equipment." The visible disconnect shall provide a visible air gap between the Customer Generator and the Distribution System in order to establish the safety isolation required for work on the Distribution System. This disconnecting device shall be readily accessible 24 hours per day by ERMU personnel and shall be capable of padlocking by ERMU personnel. The disconnecting device shall be lockable in the open position. The visible disconnect shall be a UL approved or National Electrical Manufacturers Association (NEMA) approved manual safety disconnect switch of adequate ampere capacity. The visible disconnect shall not open the neutral when the switch is open. A draw-out type circuit breaker may be used as a visual open. The visible disconnect shall be labeled "Generation Disconnect" to inform ERMU personnel. Energizing of Equipment by Generation System -The Customer Generator Shall not energize the de-energized Distribution System. The Customer shall Install the necessary padlocking (lockable) devices on Customer Generator to prevent energizing the de-energized Distribution System. Lock out relays shall automatically block the closing of breakers or transfer switches onto the de- energized Distribution System. Grounding Issues -Grounding of sufficient size to handle the maximum available ground fault current shall be designed and installed to limit step and touch potentials to safe levels as set forth in "IEEE Guide For Safety In AC Substation Grounding", ANSUIEEE Standard 80". It is the responsibility of the Customer to provide the required grounding for the Customer Generator. A good standard for this is the IEEE Std. 142-1991 "Grounding of Industrial and Commercial Power Systems". All electrical equipment shall be grounded in accordance with local, state, and federal electrical and safety codes and applicable standazds. Section 3: Types Of Interconnections -Interconnections are defined based on the manner in which the Customer Generator is connected to and disconnected from the Distribution System. Most transfer systems normally operate using one of the following four methods: