Open back switch - What's it for?


Senior Member
Anyone ever seen one of these before? That can't be approved for....well, anything but low voltage maybe, right?


Someone on another forum posted that the switches and receptacles in their house are all like this.


Senior Member
Who would have thought the IAEI supporting concealed splices!

Who would have thought the IAEI supporting concealed splices!

So would they be listed for anything but a mobile home?
Unfortunately the NEC 2014 draft is allowing this junk, sorry I meant stuff to be used in other than mobile homes:

334.40 Boxes and Fittings.
(B) Devices of Insulating Material. Self-contained switches, self-contained receptacles, and nonmetallic-sheathed
cable interconnector devices of insulating material that are listed shall be permitted to be used without boxes
in exposed cable wiring and for rewiring in repair wiring in existing buildings where the cable is concealed and fished. Openings in such
devices shall form a close fit around the outer covering of the cable, and the device shall fully enclose the part of the
cable from which any part of the covering has been removed. Where connections to conductors are by binding-screw
terminals, there shall be available as many terminals as conductors. [ROP 7?49, 7?50, 7?51]

Substantiation: Rewire is defined as providing new wire. Justification for a concealed splice when rewiring occurs seems to be difficult and the concealed splice seems to be unwarranted. However, rewiring in some cases is a burden to owners because of damage to finished surfaces. A safe repair would be a practical solution for an unsafe, existing condition. A concealed splice would always seem to be a last resort and this change would limit the application to those situations

If you think this is a bad idea, you have until 17 Oct to object. All comments must be received by NFPA by
5 p.m., EDST, Friday, October 17, 2012. It's really simple, just fill out a comment form and mail it in.

marti smith

Senior Member
mhd switch example pic.jpg

These are indeed interesting. I have never seen one before until this search, which yielded the included image. It does have a back but appears to have teeth in lieu of wirenuts, in which the conductors are pressed. ???


re member
Clarkesville, Georgia
These devices are a gold mine, many a happy day when I wouldn't have anything to do, quick Mobile Home service call and still have time for afternoon nap. Best thing they've put in mobile homes since back-stabbed devices.

Last one was hard to find though, factory forgot to provide hole in sheetrock for device, after 15 years the one that failed was inside a finished wall. 2 1/2 hours to find.