Advanced Marine Electrics and Electronics Troubleshooting A Manual for Boatowners and Marine Technicians

52 electrical systems troubleshooting

Expected Possible Possible

Measurement Result Problem Causes Solutions

Line voltage 108—132 VAC High/low Too much load on Redistribute loads on the

120 VAC the circuit. circuit.

Line voltage 220 AC 198—242 VAC High-resistance Locate high-resistance

connection within connection/device and

the circuit or at repair/replace.

the panel.

Supply voltage too Consult power company.

high/low.

Neutral-ground < 2 VAC Voltage High G—N > Current leaking from Identify source of leakage:

voltage 2 VAC neutral to ground. multiple bonding points,

equipment, or devices.

Unbalanced three- Check load balance and

phase system. redistribute load.

Triplen harmonics Oversize neutral to

returning on neutral impedance. Reduce harmonic

in three-phase effect via filter or other

system. methods.

Peak voltage 153—185 VAC High/low Supply voltage too Consult power company.

120 VAC peak voltage high/low.

Peak voltage 280—242 VAC High peak loads on Evaluate number of electronic

220 VAC line caused by devices on circuit and

electronic equipment redistribute if necessary.

on line.

Frequency 60 Hz High/low Supply frequency too Consult power company.

frequency high/low.

Source:Ideal Industries, Inc.

Voltage Troubleshooting Tips

TABLE

4-1

Physically check these possibilities and repair

or replace cables or components as needed.

This is also an area where the infrared heat

gun (see Chapter 5) can be useful in finding

the hot spot in the circuitry. Use Table 4-2 to

help you troubleshoot voltage drop problems.

Impedance Measurements

To further assist you in troubleshooting exces-

sive voltage drop, the SureTest can measure

the exact impedance (resistance) in each of the

three conductors in a circuit. Again, I know of

no other tool that has this capability.

If measured voltage drop is more than 5%,

a problem exists. Using the meter’s arrow keys,

scroll through the menu to read and compare

the impedance values for the hot, neutral, and

ground conductors. What you are looking for

here is parity among the conductors.

If impedance in one conductor is signifi-

cantly higher than another, then you’ve narrowed

down the problem. Again, loose or corroded

connections are the most probable cause, and

you must now physically search out the culprit.

If all the conductors read high, then the

cabling is probably undersized. Keep in mind