© ADB Airfield Solutions All Rights Reserved
11
2.3.2 Electrical
Requirements
1. One of the most common causes of water leakage within in-pavement fixtures is a
pinched cord-set. It is commonly caused by trapping the fixture wires when the fixture is
installed on the base can. Use caution when mounting the fixture on the base can to
prevent the incoming wires from becoming pinched.
2. If the wire conductor jacket is compromised, the entire cord-set must be replaced.
3.
Never
use electrical tape to repair the cord-set, since taping will not adequately seal the
wire conductor jacket adequately to prevent water leakage.
4.
Never
pick the fixture up using the electrical connection leads. Picking the fixture up by
the leads can cause a break in the wire conductor jacket. If the wire conductor jacket is
cut, water is drawn in during the On and Off periods due to thermal cycling of the fixture.
5. Insure that the primary isolation transformer connection splicing methods as shown in
FAA AC 150/5340-30 are followed. It is also recommended that heat shrink be used on
each primary isolation transformer connection to minimize the risk of overall series circuit
insulation resistance degradation.
6. Verify the correct current levels are coming into the fixture. Measure the fixture input
current on a sample of fixtures using a True RMS ammeter. If current is not correct at
each CCR step:
a. Verify the primary isolation transformer current is correct at all steps. If the primary
current is incorrect, the CCR may need to be calibrated or repaired.
b. Incorrect primary isolation transformer current may also be caused by low overall
series circuit insulation resistance. Meg the series circuit and repair if necessary.
7. Verify each isolation transformer wattage matches the wattage indicated in the “Electrical
8. Verify each isolation transformer ratio is correct. For a 6.6A CCR, the isolation
transformer must have a ratio of 6.6A/6.6A. For a 20A CCR, the isolation transformer
must have a ratio of 20A/6.6A.
Where to obtain the documents mentioned in this Installation Guidance document:
•
FAA AC 150/5340-30,
Design and Installation Details for Airport Visual Aids
, may be
downloaded at
http://www.faa.gov/airports/resources/advisory_circulars/
ADB Instruction Manuals may be downloaded at:
http://www.adb-airfield.com/product_center/products.aspx
. Then click on the “In-pavement
Lighting” tab and then click on the link for your particular fixture. The manuals are in the
“Literature Downloads” tab.
FAA Engineering Brief 83,
In-Pavement Light Fixture Bolts
,
may be downloaded at:
http://www.faa.gov/airports/engineering/engineering_briefs/
