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 100 A, 240V, 2-pole, NEMA 1, open transition. Typical loads are a residential service panel, a small retail or office panelboard, a well pump, a sump pump or a light commercial kitchen β circuits where the entire load can be picked up at once and where a compact wall-mounted enclosure is an advantage. The NEMA 1 enclosure is intended for indoor installation in a dry, protected space such as a mechanical room or an electrical closet. Terminations and footprint. On the 185 platform the lugs take one conductor per pole from #8 AWG to 2/0 AWG, and the whole switch is a compact wall-mount box one person can hang: this is the size that sits beside a residential panel or in a small mechanical closet and never gets a second thought. 100 A is the standard North American dwelling service and the point where a whole house transfers at once, so the contacts and the neutral plate are sized for the full load rather than for a selected circuit. 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 1 cabinet is for indoor use in a dry, protected space β a mechanical room, an electrical closet, a plant room β where the only thing it has to keep out is incidental dust and the occasional touch. It is not rain-tight and not watertight: mounting one on an exterior wall, even under a soffit, invites water in through the door seam and the conduit knockouts, and the first sign is usually a rusted mechanism rather than a tripped breaker. If the switch has to live outdoors, the 3R version of the same rating is the one to order. Matching generator. At 240V with an 0.8 power factor this switch carries approximately 19 kW of load (100 A Γ 240V Γ 0.8 = 19.2 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. 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.
