1AUSA2100F4M Series 185SE - ASCO | Automatic, 100 AMP

The ASCO Series 185SE adds service-entrance rating to the compact 185 platform, integrating the utility disconnect and the transfer mechanism in one listed enclosure for residential and light-commercial standby systems. This unit is rated 100 A, 240V, 2-pole, NEMA 3R, 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 — circuits where the entire load can be picked up at once and where a compact wall-mounted enclosure is an advantage. 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. 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 — 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 — 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. 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 — 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 240V with an 0.8 power factor this switch carries approximately 19 kW of load (100 A × 240V × 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. 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.