Product Overview
The ASCO Series 185 is a UL 1008-listed automatic transfer switch intended for optional standby systems under NEC/NFPA 70 Article 702, in residential and light-commercial installations. It is designed to work with two-wire automatic-start generators and is the entry point of the ASCO transfer switch range. This unit is rated 230 A, 240V, 2-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 β 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. Two-pole 120/240 V single-phase: two ungrounded conductors and a grounded neutral, the arrangement behind nearly every North American dwelling and behind small shops on a split-phase service. Only two poles switch, so a solid-neutral unit carries the grounded conductor straight through while a switched-neutral unit opens it β which is what you want when the generator is treated as a separately derived source and the neutral must be broken to keep the two grounding electrodes apart. 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 β 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 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. Matching generator. At 240V with an 0.8 power factor this switch carries approximately 44 kW of load (230 A Γ 240V Γ 0.8 = 44.2 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. The 185 platform uses a DIP-switch controller with factory-set pickup and dropout thresholds (198 V pickup, 187 V dropout on the normal source by default), a approximately 10-second transfer delay, a 5-minute return-to-utility stability window and a 2-minute unloaded cool-down before the generator is signalled to stop. Two-pole configuration. Both the hot and the neutral are switched, which is the normal choice for 120/240 V single-phase residential and light-commercial services and for any circuit derived from a separately derived source. 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.
