1. In switching means including support means of a dielectric material and a plurality of contact means disposed in a laterally spaced series, each of said contact means including a pair of fixed contacts extending from said support means and being spaced from one another, and a contact arm extending between and being movable in to engagement with each of the fixed contacts; removable contact isolating means of a dielectric material and comprising: common wall means extending lengthwise across at least all of said contact means spaced between the end contact means of said series and on the side of the same one of the contacts of said pairs of fixed contacts opposite from said contact arms; spaced contact isolating wall means disposed between adjacent spaced contact means and extending from said common wall means past thE other of the contacts of said pairs of fixed contacts; all of said common wall means extending from said support means to at least the ends of said pairs of fixed contacts; means retaining said contact isolating means from movement relative to said pairs of fixed contacts; and said common wall means having projections extending from its ends each engaging said one of the fixed contacts of the adjacent contact means and on the same side thereof as said contact arm.

2. In switching means including support means of a dielectric material and a plurality of contact means disposed in a laterally spaced series, each of said contact means including a pair of fixed contacts extending from said support means and being spaced from one another, and a contact arm extending between and being movable into engagement with each of the fixed contacts; removable contact isolating means of a dielectric material and comprising: common wall means extending lengthwise across at least all of said contact means spaced between the end contact means of said series and on the side of the same one of the contacts of said pairs of fixed contacts opposite from said contact arms; spaced contact isolating wall means disposed between adjacent spaced contact means and extending from said common wall means past the other of the contacts of said pairs of fixed contacts; all of said common wall means extending from said support means to at least the ends of said pairs of fixed contacts; means retaining said contact isolating means from movement relative to said pairs of fixed contacts; a hollow cover open at one end housing said contact means; said support means disposed in and closing the open end of said cover; said contact isolating means having a tab extending from between the ends of said common wall means along an adjacent edge of said support means and terminating with an enlarged free end; and one side of said cover having a slot for said tab, engaging the enlarged end of said tab at its open end and engaging said common wall means on both sides of said tab thereby urging said common wall means toward said support and contact means.

3. In switching means including support means of a dielectric material and a plurality of contact means disposed in a laterally spaced series, each of said contact means including a pair of fixed contacts extending from said support means and being spaced from one another, and a contact arm extending between and being movable into engagement with each of the fixed contacts; removable contact isolating means of a dielectric material and comprising: common wall means extending lengthwise across at least all of said contact means spaced between the end contact means of said series and on the side of the same one of the contacts of said pairs of fixed contacts opposite from said contact arms; spaced contact isolating wall means disposed between adjacent spaced contact means and extending from said common wall means past the other of the contacts of said pairs of fixed contacts; all of said common wall means extending from said support means to at least the ends of said pairs of fixed contacts; means retaining said contact isolating means from movement relative to said pairs of fixed contacts; each of said contact isolating wall means having a pair of flanges at its end adjacent said support means and spaced from said common wall means; and each flange of each of said pairs of flanges extending from the side of said contact isolating wall means opposite from the other of said pair and engaging said other of the fixed contacts adjacent thereto.

4. In switching means including support means of a dielectric material and a plurality of contact means disposed in a laterally spaced series, each of said contact means including a pair of fixed contacts extending from said support means and being spaced from one another, and a contact arm extending between and being movable into enGagement with each of the fixed contacts; removable contact isolating means of a dielectric material and comprising: common wall means extending lengthwise across at least all of said contact means spaced between the end contact means of said series and on the side of the same one of the contacts of said pairs of fixed contacts opposite from said contact arms; spaced contact isolating wall means disposed between adjacent spaced contact means and extending from said common wall means past the other of the contacts of said pairs of fixed contacts; all of said common wall means extending from said support means to at least the ends of said pairs of fixed contacts; means retaining said contact isolating wall means from movement relative to said pairs of fixed contacts; said common wall means having a flange extending therefrom along said contact isolating wall means and adjacent said support means; and said flange providing a U-shaped flange portion between each two adjacent contact isolating wall means defining a recess for the said one of the fixed contacts disposed in the space between said two adjacent contact isolating wall means, and end flange portions each extending laterally to engage the said one of the fixed contacts of a different one of said contact means at the end of said series from the adjacent contact isolating wall means.