Is it necessary to insulate dc jack from metal housing?

I have a metal dc jack going into an aluminum housing. Is it necessary to electrically insulate one from the other? The positive center pin on the jack is insulated, of course, so it seems to me the negative outer ring touching the aluminum light housing won't actually cause problems. Is this correct? It won't actually be shorting any circuits will it?

Thanks,
Alan

Normally, it should not be a problem. It depends on the rest of the circuit. For example, the battery negative is connected to the housing in most flashlights.

If you mount the emitter on a star and the star on the housing, there is no electrical contact between the LED and the housing. (So there is no need to electrically insulate the DC receptacle)

If you mount the emitter to the housing directly, there may be an electrical connection. Not al LEDs have an electrically neutral mounting pad. (So there may be a need to electrically insulate the DC receptacle)

Same for the driver board. You can either mount it electrically insulated (on a thermal pad for example, like the Taskled driver boards) or electrically connected to the housing.

Again, in flashlights the driver is usually soldered to the pill so there is electrical contact - This usually is the negative battery lead connection.