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Dwyer 1950G-1-B-120-NA Explosion-Proof Differential Pressure Switch, 0.4-1.6 in WC, 120 VAC, SPDT, UL/CSA/FM Class I Div 1

Dwyer 1950G-1-B-120-NA Explosion-Proof Differential Pressure Switch, 0.4-1.6 in WC, 120 VAC, SPDT, UL/CSA/FM Class I Div 1

Dwyer

MSRP: $631.40
$502.75
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SKU:
1950G-1-B-120-NA
Condition:
New
Availability:
8 In Stock
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Range0.4-1.6 in WC
Deadband0.11 to 0.29 in WC
Supply Voltage120 VAC
Switch TypeSPDT, 10A
Process Connection1/8 in FNPT
EnclosureIP54, NEMA 3/7/9
Hazardous Loc.Class I Div 1
CertificationsUL, CSA, FM

The Dwyer 1950G-1-B-120-NA is an explosion-proof differential pressure switch with a setpoint range of 0.4-1.6 in WC, factory-calibrated SPDT relay output, and a compact cast-aluminum enclosure rated NEMA 3/7/9 (IP54). Powered by 120 VAC, it is UL, CSA, and FM listed for Class I, Groups A (UL only), B, C, D; Class II, Groups E, F, G; and Class III hazardous atmospheres, and is fully compatible with natural gas and other combustible gases. An external setpoint adjustment screw on the top of the housing lets technicians dial in the trip point without opening the enclosure, and a captive cover screw simplifies field wiring at the internal terminal block.

Best for: duct static pressure monitoring, combustion-air proving on industrial burners, and dust-collector differential alarms. Particularly suited to outdoor and all-weather installs where rain-tight (IP54) and explosion-proof housing are required on the same control.
2-YEAR
WARRANTY
Manufacturer-backed coverage. Dwyer Series 1950G switches carry a two-year limited warranty against defects in materials and workmanship. ZOT Supply is an authorized Dwyer distributor; product ships factory-new with full manufacturer warranty intact and access to Dwyer technical support.

Key Features

Explosion-Proof Aluminum Housing

Compact cast-aluminum enclosure listed for Class I Groups A (UL), B, C, D; Class II Groups E, F, G; and Class III atmospheres. About half the weight and footprint of conventional XP switches.

Natural Gas Compatible

Wetted parts are rated for air and compatible combustible gases including natural gas, making the 1950G suitable for gas-train pressure proving and combustion safety interlocks where standard pressure switches cannot be used.

External Setpoint Adjustment

Slotted screw on top of the housing lets the trip point be dialed in without removing the cover or de-classifying the area. Adjustment range: 0.4-1.6 in WC.

Easy-Access Internal Wiring

Captive cover screw swings the top plate aside for fast access to the SPDT relay terminals (COM, NO, NC) and the 120 VAC supply terminals. 1/2 in FNPT conduit entry.

Rain-Tight Outdoor Rated

IP54 and NEMA 3 enclosure rating means the same switch covers indoor and outdoor service. Vent drain plug can be rotated to clear condensate buildup in damp installations.

Multi-Agency Hazardous Certifications

UL Listed, CSA and FM Approved for the same hazardous-location groups. -NA suffix denotes North-American agency listings; ATEX, IECEx, UKCA, CCC, KCs, and PESO versions also available from the factory.

Technical Specifications

SpecificationValue
Model1950G-1-B-120-NA
Operating Range0.4-1.6 in WC
Approx. Deadband at Min. Setpoint0.11 in WC
Approx. Deadband at Max. Setpoint0.29 in WC
ServiceAir and compatible combustible gases (natural gas compatible)
Pressure Limit, Continuous45 in WC (11.2 kPa)
Pressure Limit, Surge10 psig (68.95 kPa)
Temperature Limits0 to 140 F (-17 to 60 C)
Switch Type1 Form C relay, SPDT
Electrical Rating10 A @ 120/240 VAC, 28 VDC; resistive 50 mA @ 125 VDC
Power Supply120 VAC (+/-10%)
Electrical ConnectionsInternal terminal block (COM, NO, NC, plus supply)
Conduit Entry1/2 in female NPT
Process Connections1/8 in female NPT, high and low ports
Enclosure RatingNEMA 3, NEMA 7, NEMA 9, IP54
Hazardous Location ListingsUL, CSA, FM listed: Class I Groups A (UL only), B, C, D; Class II Groups E, F, G; Class III
Wetted MaterialsContact factory
Mounting OrientationDiaphragm in vertical plane
Setpoint AdjustmentExternal screw on top of housing
Weight2 lb 15.7 oz (1.35 kg)
Manufacturer Part Number1950G-1-B-120-NA

Documentation

PDFCatalog DatasheetPDFInstallation and Operating Manual (Bulletin E-57G)

Frequently Asked Questions

What pressure range does the 1950G-1-B-120-NA cover?
This variant is the -1 range, with an adjustable setpoint of 0.4-1.6 in WC. Approximate deadband is 0.11 in WC at the minimum setpoint and 0.29 in WC at the maximum setpoint. The diaphragm is rated for 45 in WC continuous overpressure and 10 psig surge.
Is the 1950G rated for use with natural gas?
Yes. The Series 1950G is specifically designed with wetted materials compatible with natural gas and other combustible gases, which is its primary differentiator from the standard Series 1950. This makes it suitable for gas-train pressure proving, combustion-air supervision, and other natural-gas applications in Class I Div 1 hazardous locations.
What hazardous-location ratings does the -NA suffix carry?
The -NA suffix denotes the North-American certification package: UL Listed, CSA Approved, and FM Approved for Class I Groups A (UL only), B, C, D; Class II Groups E, F, G; and Class III atmospheres. ATEX, IECEx, UKCA Ex, China CCC, Korea KCs, and India PESO versions are available with different suffixes.
Can the switch be installed outdoors?
Yes. The cast-aluminum enclosure is rated NEMA 3 / IP54, meaning it is rain-tight and suitable for outdoor installation. The vent drain plug at the bottom of the housing can be rotated periodically to clear any condensate that accumulates inside the diaphragm chamber.
How do I adjust the setpoint without opening the enclosure?
Remove the small plastic cap on top of the housing, then turn the slotted adjustment screw clockwise to raise the trip point and counter-clockwise to lower it. Replace the cap when finished. The internal SPDT relay only needs to be accessed for electrical wiring. Always verify the setpoint with a calibrated manometer.
What is the difference between the 120 VAC variant and the other voltage options?
The supply voltage powers only the internal relay coil and indicator circuit; the switching contacts themselves are rated 10 A at 120/240 VAC or 28 VDC regardless of supply. This SKU is the 120 VAC variant. ZOT Supply also stocks the 24 VDC variant under the same Series 1950G family; Dwyer additionally offers a 240 VAC factory option. Choose the supply voltage that matches the control transformer or DC bus already available at the panel.
Brand:
Dwyer
Series:
1950G
Product Type:
Explosion-Proof Differential Pressure Switch
Operating Range:
0.4-1.6 in WC
Range Code:
-1
Deadband at Min Setpoint:
0.11 in WC
Deadband at Max Setpoint:
0.29 in WC
Service:
Air, Compatible Combustible Gases, Natural Gas
Switch Type:
SPDT, 1 Form C Relay
Electrical Rating:
10 A at 120/240 VAC, 28 VDC
Supply Voltage:
120 VAC
Process Connection:
1/8 in FNPT
Conduit Entry:
1/2 in FNPT
Pressure Limit (Continuous):
45 in WC, 11.2 kPa
Pressure Limit (Surge):
10 psig, 68.95 kPa
Temperature Range:
0 to 140 F, -17 to 60 C
Enclosure Rating:
NEMA 3, NEMA 7, NEMA 9, IP54
Hazardous Location:
Class I Groups A (UL), B, C, D
Certifications:
UL Listed, CSA Approved, FM Approved
Mounting Orientation:
Diaphragm Vertical
Setpoint Adjustment:
External Screw
Weight:
1.35 kg, 2 lb 15.7 oz
Country of Origin:
USA
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