An electrode assembly may include an electrode support made of a first electrically insulative material and an electrode on the electrode support, the electrode having a working surface extending generally transverse to a thickness of the electrode. The electrode assembly may further include an insulative spacer retained in the electrode and made of a second electrically insulative material. The second electrically insulative material may be different from the first electrically insulative material. The insulative spacer of the electrode assembly may have a body portion extending into the thickness of the electrode, and a head portion protruding beyond the working surface of the electrode.