What makes Appleton EDS tumbler switches explosionproof and dust-ignitionproof?

Appleton EDS Factory Sealed Tumbler Switches are UL listed for NEC/CEC Class I, Division 1 and 2, Groups B (select 1-gang units), C, D; Class II, Division 1 and 2, Groups E, F, G; Class III; and NEMA 3, 7 BCD, 9EFG. They prevent arcing of enclosed switches in ignitable atmospheres during connect and disconnect operation of lighting and light power loads. The Appleton catalog names chemical plants, petrochemical plants, refineries, and other process industries as installation locations.

All EDS enclosures have external mounting lugs, smooth rounded integral bushings in each hub to protect conductor insulation, and an internal ground screw. Standard body and cover material is malleable iron. The sealing chamber on select models is copperfree aluminum with a maximum copper content of 4/10 of 1 percent. Handles are nylon 6/6, and cover, body, and sealing chamber assemblies use corrosion resistant stainless steel hex head cap screws for flame-tight construction.

How does Appleton EDS factory sealing contain arcs without external sealing fittings?

Factory sealed EDS switches are designed to a UL Standard so that any arcing devices are contained within an explosionproof labyrinth switch, which is a standard switch on some models, or within a separate sealing chamber on select models. Tumbler switch devices are approved for installation without additional external sealing fittings.

All 20 Amp 4-way models and all 30 Amp models use a switch enclosed in a separate sealing chamber. Smooth double-face, accurately ground surfaces on the sealing chamber flange mate with the cover and body to provide positive flame-tight construction. The sealing chamber has prewired factory sealed pigtail leads to the switch. All 20 Amp models excluding 4-way use the explosionproof labyrinth switch construction instead.

Which Appleton EDS models carry Class I Group B ratings and which are limited to Groups C, D?

1/2 inch and 3/4 inch 1-gang EDS units are suitable for Class I, Group B, in addition to Class I, Groups C and D, Class II, Groups E, F and G, and Class III. Shaded areas in the EDS product selection tables indicate items suitable for Class I, Group B as well as Groups C and D.

Factory assembled switch assemblies, mounting bodies, and blank bodies for brazed hubs carry NEC/CEC Class I, Division 1 and 2, Groups C, D only, not Group B. Tandem bodies require external seals installed within 1.5 meters, or 5 feet, of each conduit entrance for Class I, Groups C and D.

How do you choose between front operated and rocker arm operated handles?

Appleton EDS switches are available with either front operated or side rocker arm handles. Each handle type may be locked in the ON or OFF position. Front operated models use a front cover, while rocker arm operated models use a rocker cover and chamber. Both handle types are available in 1-pole, 2-pole, 3-way, and 4-way configurations.

20 Amp models are rated 1 HP at 120 Vac and 2 HP at 240 Vac. 30 Amp models are rated 2 HP at 120 Vac or 240 Vac. Aluminum rocker arm covers are not available. Dimensions are the same for front operated and rocker arm operated 1-gang and 2-gang units: 136.7 mm by 155.7 mm by 19.8 mm for 1/2 inch and 3/4 inch hubs, and 139.7 mm by 160.3 mm by 23.9 mm for 1 inch hubs.

What catalog numbering system applies to Appleton EDS switch bodies and hubs?

EDS tumbler switches may be ordered in single through five gang deep malleable iron blank bodies with brazed hubs as specified at any location. They may also be ordered with tandem malleable iron boxes and additional brazed hubs. Standard malleable iron single and 2-gang tumbler switches may be ordered with additional brazed hubs as specified. Single and 2-gang tumbler switches may be ordered with aluminum boxes with additional brazed hubs.

For custom hub arrangements, send a sketch indicating sizes and locations for brazed hubs on the body or bodies selected. Orient the sketch so the cover opening faces front and mounting lugs face upward and downward. The box wall opposite the cover is the back of the box. Use the EFD Cast Device Boxes Ordering Information to construct complete catalog numbers. The symbol table uses 0 for blank, 1 for 1/2 inch threaded hub, 2 for 3/4 inch threaded hub, 3 for 1 inch threaded hub, and 1E, 2E, and 3E for the corresponding brazed union hubs. Example catalog number: EFD-3NL-8-23203E.

Why do 20 Amp 4-way and all 30 Amp models use a separate sealing chamber?

The separate sealing chamber construction is used on 20 Amp 4-way and all 30 Amp models because these switches are enclosed in a sealing chamber that provides positive flame-tight construction. The flange surfaces are accurately ground to mate with the cover and body, and the chamber contains prewired factory sealed pigtail leads to the switch.

In contrast, all 20 Amp models excluding 4-way use the explosionproof labyrinth switch construction. Catalog entries marked with a diamond symbol contain a standard switch and sealing chamber. This distinction matters when selecting replacement switch assemblies because 20 Amp 4-way and 30 Amp models require the sealing chamber, while other 20 Amp models do not.

What materials and finishes are specified for Appleton EDS enclosures?

Standard EDS body and cover are malleable iron. Sealing chambers on select models are copperfree aluminum with a maximum copper content of 4/10 of 1 percent. Handles are nylon 6/6. Optional nameplate mounting brackets are corrosion resistant stainless steel. Cover, body, and sealing chamber assemblies use stainless steel hex head cap screws.

Standard finishes for tumbler switches are a triple coat consisting of zinc electroplate, chromate, and epoxy powder coat. Optional 1-gang and 2-gang copperfree aluminum bodies and covers are available by adding suffix -A.

How do NPBRKT nameplate brackets mount on Appleton EDS control stations?

NPBRKT nameplate mounting brackets make circuit description and identification easy. The bracket with a blank silver and black nameplate for EFDB series has catalog number NPBRKT-EFDB. To order a bracket with a control station, add suffix -NPBRKT to the end of the catalog number. Engraved nameplates are limited to a maximum of 2 lines with 12 characters, including spaces, per line.

Mount the bracket between the cover screws and the cover. Do not mount the bracket between the ground joint flame path between the cover and backbox. Torque cover screws to 35 inch-pounds. Pre-drilled holes in the bottom of the bracket allow direct mounting to control stations with existing cover bolts, and pre-drilled holes in the middle allow mounting of a customer circuit identification nameplate, with epoxy glue as an option. Phenolic nameplates are not included.

Summary

Appleton EDS Factory Sealed Tumbler Switches are NEC/CEC Class I, Division 1 and 2, Groups B (select 1-gang units), C, D; Class II, Groups E, F, G; Class III; NEMA 3, 7 BCD, 9EFG rated.
Factory sealed construction contains arcing devices without external sealing fittings; 20 Amp 4-way and all 30 Amp models use a separate sealing chamber.
1/2 inch and 3/4 inch 1-gang EDS units carry Class I Group B ratings, while factory assembled switch assemblies and mounting bodies are limited to Groups C, D.
Front operated and rocker arm operated handles are both lockable, with 20 Amp models rated 1 HP at 120 Vac and 2 HP at 240 Vac, and 30 Amp models rated 2 HP at 120 Vac or 240 Vac.
Custom hub arrangements use the EFD Cast Device Boxes Ordering Information symbol table, and NPBRKT brackets mount between cover screws and cover with cover screws torqued to 35 inch-pounds.

Step-by-step

Select mounting body catalog number from dead-end or feed-thru 1-gang, 2-gang, or tandem EFD bodies.
Select cover catalog number with the desired 1-pole, 2-pole, 3-way, or 4-way switch operation.
Add suffix -A to order 1-gang or 2-gang copperfree aluminum bodies and covers.
For custom hub arrangements, submit a sketch with hub sizes, locations, cover face orientation, and mounting lug orientation to construct the brazed hub catalog number.
Mount the NPBRKT bracket between cover screws and cover, torque cover screws to 35 inch-pounds, and add suffix -NPBRKT to the control station catalog number to order the bracket preinstalled.

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Appleton EDS Factory Sealed Tumbler Switches: 20 and 30 Amp Selection for Class I Groups B, C, D