Product Overview
The ASCO Series 300 Service Entrance (SE) version combines the transfer function with a service-entrance rated disconnect in a single listed enclosure, so the switch can be installed at the point where utility power enters the building instead of requiring a separate service disconnect ahead of it. This unit is rated 600 A, 220V, 3-pole, NEMA 3R, open transition. Typical loads are a central plant, a multi-tenant distribution section, a water or wastewater pump station, or a process line β installations where the switch is a free-standing assembly and fault coordination with the service equipment matters as much as the transfer function. The NEMA 3R enclosure is rain-tight and rated for outdoor mounting against a wall or on a pad, so the switch can sit next to an exterior generator without an additional weather shelter. Terminations and footprint. Two conductors per pole from 2/0 AWG to 600 kcmil, in a 24 in by 63 in by 17 in free-standing enclosure weighing 300 to 320 lb. At 600 A the switch normally sits on a housekeeping pad beside the service equipment rather than on a wall, the feeder is pulled with a rope and a tugger, and the terminations are laid out so they stay reachable with the line side energised. Two 600 kcmil per phase is a stiff pull β plan the conduit body and the bend radius before the concrete is poured. Neutral configuration. The neutral is switched β it opens and closes with the phase poles as one more pole. You need this when the generator is wired as a separately derived source with its own grounding electrode and its own main bonding jumper: leaving the neutral solid would tie the two grounding systems together through the neutral, put objectionable current on the grounding conductor and leave the generator frame at a potential above earth during a fault. It costs one more pole and one more set of contacts to maintain, but on a separately derived system it is not optional, and an inspector will look for it. Enclosure. The Type 3R cabinet is rain-tight, not watertight: it is built for outdoor mounting against a wall or on a pad, with a hooded or sloped top that sheds water and a gasketed door that keeps driven rain out. What it does not do is keep out dust or hose spray, and the installation still has to do its part β conduit entries need drip loops or sealing hubs so water running down the conduit cannot track into the enclosure, and the mounting surface has to drain. A 3R unit on a north wall in a coastal yard will outlast three indoor units in the same spot, which is why it is the default for anything not under a roof. Service-entrance rating. This is the SE version, which means the assembly is listed as service equipment in its own right: the utility disconnect and the transfer mechanism share one enclosure, and there is no separate main breaker or service disconnect ahead of it. Three things follow from that. The neutral bus is the service neutral and the main bonding jumper lands inside this enclosure, so the grounding electrode conductor terminates here rather than at a separate disconnect. The short-circuit current rating applies to the whole assembly, not just to the switch, and it has to be checked against the available fault current at the service point. And the utility will want to see the listing before they energise it β a standard transfer switch installed ahead of the service disconnect without an SE rating is a common inspection failure. What the extra cost buys is one enclosure, one set of terminations and one less place for a bonding error. Matching generator. At 220V with an 0.8 power factor this switch carries approximately 115 kW of load (600 A Γ 220V Γ 0.8 = 115.2 kW, single-phase two-wire). Size the standby generator so that its standby rating meets or exceeds that figure, and confirm the generator's two-wire automatic-start contacts are compatible with the transfer switch controller. Controller. This unit carries the ASCO Group G controller: a 128 Γ 64 graphical LCD with switch-position, source-availability, common-alarm and not-in-auto indication. Transfer and re-transfer delays, engine cool-down and the in-phase transfer timer are all set from the membrane keypad rather than from DIP switches, with ranges up to 60 min 59 s. The Group G controller supports both open transition and delayed transition, and accessory 11BE adds RS-485 communication at 9,600β115,200 bps, a seven-period programmable exerciser and a 300-event log. Three-pole configuration. The three phase conductors are switched with a solid neutral. This is the standard arrangement where the neutral is bonded at the service and must not be opened by the transfer switch. Supply. Supplied as a genuine ASCO Power Technologies (Schneider Electric) unit, brand new and factory original, packed for export from our Dongguan warehouse. Ask us for the outline drawing, wiring diagram and data sheet for this exact catalog number.
