Product Overview
The ASCO Series 185 manual transfer switch is the non-automatic member of the 185 family: the same compact UL 1008-listed transfer mechanism, operated by hand through a maintenance handle instead of a controller. It suits small residential and light-commercial standby systems where the owner starts the generator personally. This unit is rated 200 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. One conductor per pole, #14 AWG to 4/0 AWG, in the 18 in by 31 in by 13 in cabinet at roughly 75 lb. 200 A is the standard light-commercial service size and the point where the switch normally covers the entire board β lighting, receptacles and a small mechanical load β rather than a selected group. The wide lug range means the same unit accepts a #6 feeder or a 4/0, which is useful when a service is upgraded later without replacing the switch. 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 38 kW of load (200 A Γ 240V Γ 0.8 = 38.4 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. Operation. There is no controller on this unit and no automatic signal path to the generator: it is switched by hand through a mechanically interlocked operating handle, so the two sources can never be closed on each other. The sequence is deliberate and always the same β start the generator manually, let it reach rated voltage and frequency, throw the handle to the emergency side, and reverse it once the utility is back and the generator has run unloaded long enough to cool. What that buys is the shortest possible list of things that can fail: no voltage sensing board, no timer, no exerciser, nothing to drift out of calibration. What it costs is a person on site at the moment of transfer, which is why this version suits a workshop, a farm, a temporary supply or a maintenance bypass position rather than an unattended building. 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.
