Test integrity of AC grounding system

Question 1

what is the most important wire on the boat and why?

Answer 1

AC grounding system. It insures that the OCPD will activate in the event of a fault

Question 2

when working with AC what personal precautions should you take?

Answer 2

Remove all jewelry and metallic objects, make sure hands are dry, use lock out tag out precedures

Question 3

what steps should you take when testing AC grounding system with no Galvanic Isolator or Isolation Transformer?

Answer 3

1. Turn off breaker at pedestal and remove shore power cord
   2.observe plug
   3.take shore power cord aboard vessel to a location with access to the engine - terminal or its bus
   4.with an ohm meter measure resistance between the grounding conductor and the shore power cord the reading should be a maximum of 25MA
   i if reading is higher, repairs should be made ASAP

Question 4

what steps do you need to take to test a grounding system with a Galvanic Isolator but no Isolation Transformer

Answer 4

1. turn off breaker at pedestal and remove shore power cord.
2. inspect shore power cord
3. take shorepower cord to the location of the Galv. Isolator
4. with volt-ohm meter measure the resistance between the grounding conductor on the shorepower cord and the dockside connection of the galvanic isolator
5. the reading should be 25MA max and if more than that repairs should be made ASAP
6. with volt-ohm meter measure the resistance between the grounding conductor on the secondary side of the transformer and the engine negative terminal or its bus
7. reading and procedure is the same as step 5

Question 5

What steps do you need to take to test the AC grounding system with an Isolation Transformer and no Galvanic Isolator?

Answer 5

1. turn off breaker at pedestal, unplug power cord and check it.
2. Take the shore power cord to location of the Isolation Transformer.
3. with volt-ohm meter measure the resistance between the grounding conductor on the shore power cord and the dockside connection of the isolation transformer
4. the reading should be a max. of 25MA, if higher, repairs should be made ASAP
5. observe the secondary side of the transformer nueteral AND the secondary side of the case/grounding conductor. this constitutes a Nueteral- ground connection. With out this connection between the neuteral and ground there is no safety ground aboard the vessel. if not present, this connection must be made.
6. with volt-ohm meter measure the resistance between the grounding conductor and the secondary side and the engine negative terminal or its bus. the reading should be no more than 25MA

Question 6

When do you need a nuteral ground connection on a boat and why?

Answer 6

With an Isolation transformer, because it is a newly derived source of power

Question 7

what tools will you need to test the AC grounding system?

Answer 7

Lockout tag out tags
Volt-ohm meter
extension wire with alligator clips