Fill in the blank.
For boilers designed such that fault currents do not pass through the pressure vessel, and the pressure vessel is electrically isolated from the electrodes, all exposed non-current-carrying metal parts, including the pressure vessel, supply, and return connecting piping, shall be _________. For all other designs, the pressure vessel containing the electrodes shall be isolated and _________ from ground.
A) insulated / connected
B) grounded / electrically insulated
C) bonded / isolated
D) none of the above
Scroll Down to See the Answer
Answer: B
As outlined in Sec. 425.85 of the 2017 NEC, “For those boilers designed such that fault currents do not pass through the pressure vessel, and the pressure vessel is electrically isolated from the electrodes, all exposed non-current-carrying metal parts, including the pressure vessels, supply, and return connecting piping, shall be grounded. For all other designs, the pressure vessel containing the electrodes shall be isolated and electrically insulated from ground.”
Owen is the owner and president of National Code Seminars and the holder of master electrician certifications in 46 states. He can be reached at [email protected].
