3ATSA30230CG0F Series 300 - ASCO | Automatic, 230 AMP

The ASCO Series 300 is a UL 1008-listed automatic transfer switch built for commercial, institutional and light-industrial standby power. It monitors both the utility and the generator source and transfers the load automatically when the normal source falls outside acceptable limits, then returns it once the utility is restored and stable. This unit is rated 230 A, 208V, 3-pole, NEMA 3R, open transition. Typical loads are a whole-building distribution panel, a rooftop packaged unit group, a small data or telecom room, a clinic or a restaurant — installations where the transfer switch is sized to the full service and must coordinate with the upstream overcurrent protection. 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. Still one conductor per pole from #14 AWG to 4/0 AWG, but the cabinet grows to 18 in by 48 in by 13 in and the weight to about 133 lb. That jump from the 31 in wide box to the 48 in wide box is the largest proportional step in the family: 230 A is the top of the frame that uses 4/0 as its practical maximum, and the extra width is what gives four 4/0 conductors room to bend without crowding the mechanism. Service arrangement. This is a 208Y/120 V three-phase four-wire switch — the service found in office buildings, retail strips, clinics and small data rooms, where one panelboard feeds 208 V three-phase loads and 120 V receptacle circuits off a solid neutral. The neutral is not switched, because it is bonded at the service and opening it would defeat ground-fault sensing. Neutral configuration. The grounded conductor is solid: it runs straight through on a bolted neutral plate and is never opened. That is the correct choice when the transfer switch is not a separately derived source — the generator neutral is bonded to the same grounding electrode system as the utility, so the neutral is one continuous current-carrying conductor end to end and breaking it would serve no purpose. It is also the cheaper of the two arrangements and has one fewer set of moving contacts to inspect, which is why it is the default on most commercial retrofits where the existing service neutral is already bonded. 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 — 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. Matching generator. At 208V with an 0.8 power factor this switch carries approximately 66 kW of load (230 A × 208V × √3 × 0.8 = 66 kW, three-phase). 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 × 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 9,600–115,200 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.