cable clamps on metal boxes

[mickey1943]

The metal boxes I am using do not have the internal screw down wire clamps so I am using the kind that you fasten to the box with a nut. Is it allright to run more than one cable through a clamp or must each cable have a seperate clamp?

[Rewired]

Here again it depends on what code says for the area you are in,
Where I live it used to be common practice to do this but that has since changed over the past few years for some reason. To be safe, using one cable per connector won't hurt.
Oh ya, another note, if you are using those "single screw" type connectors (usually called L-16's') on romex, if it is allowed in your area to do so, Beware of some brands that are designed where the clamping screw can easily bind and / or thread right through the clamping "shoe" and end up right in your cable. I have been there, done that and it really sucks! If yours look like that can happen,(end of clamping screw is visable on the side of the clamping shoe that contacts the cable)... Tighten them with extreme care or better yet, use a different brand or style of connector where the clamping screw has no possible way of contacting the cable in any way!

A.D

[HayZee518]

New work metal, old work metal boxes usually have a wire clamp inside fastened by one screw. The clamp has a portion of it embossed above the base metal so it clamps the wire. Very often this risen surface bites into the wire right through the jacket. Be careful! Don't reef down on the cable but just enough to make it snug.
Also, check your local codes on cable fill within the box. Here in the US each wire is counted as one all grounds are considered as one, each clamp is counted as one, each device is counted as one. Legally you can't exceed the number of cables within a box - there's a chart for this. Boxes are marked for the cubic inch displacement for conductors within.

[volts]

mickey: Check the box. It may have a tapped hole for a clamp. I save clamps for that reason. Around here (MD) they poke two 14awg Romex thru one nutted connector(particularly into panels)which is the wide-mouth type, of course.

[HayZee518]

VOLTS - that is typical for most installations. When I was in MA that was common practice only IF the connector was engineered to accept more than one cable. OZ Gedney two screw connectors had provisions for only one cable - RACO was big enough to take two cables.