Product Description
Benshaw RSC-85/4-6AC120 RediStart Contactor — 85A, 4-Pole, 120V AC Coil
The Benshaw RSC-85/4-6AC120 is an 85A, 4-pole IEC contactor from the Benshaw RediStart RSC series, rated for 30 HP at 230V and 60 HP at 460V three-phase. The coil operates on 120V AC. The contactor mounts on standard 35mm DIN rail with screw terminals and ships with no built-in auxiliary contacts — top-mounted auxiliary blocks can be added as needed. This 4-pole unit is specifically designed for use as the bypass contactor in Benshaw RB2 and RB2 series soft starter chassis, making it a critical replacement part for those applications. Also referenced as Daikin McQuay part number 300043218 in HVAC applications.
Quick Specifications
- Current Rating: 85A (AC-3)
- Poles: 4-pole
- Coil Voltage: 120V AC (60 Hz)
- HP Rating: 30 HP @ 230V / 60 HP @ 460V (3-phase)
- NEMA Size: Size 3
- Auxiliary Contacts (included): None — top-mounted aux blocks available
- Terminal Type: Screw terminals
- Mounting: 35mm DIN rail
- Max Switching Voltage: 660V AC
- Warranty: 2 years (Benshaw Promise)
- Primary Application: Bypass contactor for Benshaw RB2 / RB2 soft starter chassis
- OEM Cross-Reference: Daikin McQuay 300043218
- Part Number Variants: RSC-85/4-6AC120 = RSC-85-4-6AC120 (slash and hyphen formats both used)
HP Ratings by Voltage
| Supply Voltage | HP Rating (3-Phase) | Typical Application |
|---|---|---|
| 230V AC (3-phase) | 30 HP | Pumps, fans, compressors |
| 460V AC (3-phase) | 60 HP | Soft starter bypass, HVAC, industrial |
| Up to 660V AC | Per application | Resistive and inductive load switching |
RSC-85/4 vs. RSC-85 — 4-Pole vs. 3-Pole
| Specification | RSC-85/4-6AC120 (this item) | RSC-85-6AC120 (3-pole) |
|---|---|---|
| Current Rating | 85A (AC-3) | 85A (AC-3) |
| Poles | 4-pole | 3-pole |
| Coil Voltage | 120V AC | 120V AC |
| HP @ 460V | 60 HP | 60 HP |
| Aux Contacts Included | None | 2 NO / 2 NC (side-mounted) |
| Overload Relay | Not applicable (bypass use) | SPO-85 series |
| Primary Use | Soft starter bypass | Motor starter |
Product Features
- 4-Pole Configuration — Bypass Contactor Design: The RSC-85/4-6AC120 uses four switched poles rather than the standard three used for motor starting. This 4-pole configuration is required for the bypass function in Benshaw RB2 soft starters, where the contactor bridges around the soft starter's SCR power stack once the motor reaches full speed, eliminating heat dissipation and SCR wear during run mode.
- No Built-In Auxiliary Contacts: Unlike the 3-pole RSC-85-6AC120 which includes two sets of side-mounted auxiliary contacts, the RSC-85/4-6AC120 ships with no built-in auxiliary contacts. Top-mounted auxiliary contact blocks can be added if control signalling circuits are required for the bypass function.
- Benshaw RB2 Soft Starter Bypass: The RSC-85/4-6AC120 is the specified bypass contactor for Benshaw RB2 and RB2 series open-chassis soft starter units. When replacing this contactor in an existing RB2 installation, confirm the soft starter chassis model and existing wiring before ordering to ensure compatibility.
- IEC-Rated Construction: Built to IEC standards for resistive and inductive loads up to 660V AC. Rated for 85A AC-3 continuous duty at NEMA Size 3 ratings.
- 35mm DIN Rail Mounting: Mounts on standard 35mm DIN rail with screw terminals for straightforward panel installation.
- Draw-Out Cassette-Type Coil: RSC series contactors feature a draw-out cassette coil design with wide voltage range coils and integral coil surge suppression — key advantages for long-term reliability in soft starter bypass applications where the contactor may cycle infrequently but must operate reliably when called upon.
- 2-Year Benshaw Warranty: Every Benshaw RediStart contactor carries a full two-year warranty — twice the standard one-year warranty offered by most competing brands. Benshaw calls this the Benshaw Promise.
- Daikin McQuay OEM Part: The RSC-85/4-6AC120 is used as an OEM component in Daikin McQuay HVAC systems under part number 300043218. If your equipment documentation references the Daikin McQuay number, this Benshaw contactor is the correct replacement.
Stock Item – Order before 4:00 PM EST for Same-Day Shipping.
Frequently Asked Questions
What is the RSC-85/4-6AC120 used for?
The RSC-85/4-6AC120 is a 4-pole bypass contactor primarily used in Benshaw RB2 and RB2 series open-chassis soft starters. In a soft starter bypass circuit, the contactor closes across the soft starter's power section once the motor reaches full operating speed, allowing full-voltage current to flow through the contactor rather than the SCRs. This reduces heat generation and extends the life of the soft starter's power components during continuous run operation.
What is the difference between RSC-85/4-6AC120 and RSC-85-6AC120?
These are two distinct contactors sharing the same 85A current rating and 120V AC coil. The RSC-85/4-6AC120 is a 4-pole contactor with no built-in auxiliary contacts, designed for soft starter bypass applications. The RSC-85-6AC120 is a 3-pole contactor that includes two side-mounted auxiliary contact blocks (2 NO / 2 NC) and is designed for standard motor starting with an SPO-85 overload relay. They are not interchangeable. If you are servicing an RB2 soft starter, you need the 4-pole RSC-85/4 version.
Is there an RC series replacement for the RSC-85/4-6AC120?
The Benshaw RC series introduced as the successor to the RSC line offers 3-pole contactors (such as the RC-85A-56AC120), but a 4-pole RC equivalent for the RSC-85/4 has not been identified in current production listings. If you need a current-production 4-pole 85A bypass contactor for an RB2 soft starter application, contact Kent Electrical Supply at 1-800-222-5129 — we can confirm current availability and any factory-recommended substitution.
Is the RSC-85/4-6AC120 the same as Daikin McQuay part number 300043218?
Yes — the Benshaw RSC-85/4-6AC120 is used as an OEM component in Daikin McQuay HVAC equipment under their internal part number 300043218, where it is described as “CONTACTOR BYPASS 85A 4P 120V.” If your Daikin McQuay service documentation references part number 300043218, the RSC-85/4-6AC120 available from Kent Electrical Supply is the correct replacement.
What does the "/4" mean in the part number RSC-85/4-6AC120?
The “/4” in the RSC-85/4-6AC120 designates the 4-pole configuration. The base RSC-85 frame is a 3-pole contactor; adding “/4” to the catalog number specifies the 4-pole version. In the URL and some catalog listings this appears as a hyphen (RSC-85-4-6AC120) rather than a slash, but both refer to the same contactor. Always verify “4-pole” or “4P” on the product label before installation.
Does the RSC-85/4-6AC120 qualify for same-day shipping?
Yes — when in stock, the RSC-85/4-6AC120 ships same business day from Kent Electrical Supply’s warehouse in Emmaus, PA when ordered before 4:00 PM EST. Current stock quantity is shown on this page. For bulk orders or questions about availability, call us at 1-800-222-5129 or text your RFQ to 484-425-0652.
