MAINTENANCE
INFORMATION
DATE :

MAY 2015

SUBJECT :

MI15-24

SECTION: 06 - Electrical

POWER CABLES INSPECTION GUIDELINES

APPLICATION
Model

VIN

All Prevost models

DESCRIPTION
It is important to carry out a regular inspection of the vehicle power cables. Power cables in poor condition
can be the cause of failures and serious damages in the engine compartment.
Please note that some images in this document may represent arrangements different from those found
on vehicles of former generations. However, inspection criteria and points to check presented in this
document remain applicable in essence for all models of Prevost vehicles.

POWER CABLES MAINTENANCE SCHEDULE
DESCRIPTION

INTERVAL

Perform power cables inspection

Every 3 months

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POWER CABLES
‒

The power cables are those through which flow the highest currents. These cables are those with the
largest electrical conductor diameters on the vehicle.

‒

The power cables are 1/0, 2/0, 3/0 wire gauges respectively Ø0.325in, Ø0.365in, Ø0.409in.
Note: not to be confused with the 1, 2, 3 wire gauges that are actually smaller.

‒

There are power cables at the following locations:



On the alternators positive (+) stud terminal and from there, up to Bussman junction block in the
electrical compartment (Figure 1, Figure 2, Figure 3).

Figure 1

Figure 2: Bussman Junction Block - X3 Series.


Figure 3: Bussman Junction Block - H3 Series.

On the starter positive (+) stud terminals and from there, up to Bussman junction block in the
electrical compartment (Figure 4, Figure 5).

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Figure 4

Figure 5: starter cables


In the electrical compartment, connected to Bussman junction block (Figure 6).

Figure 6

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

In the battery compartment between battery no2 and master relay R1 (Figure 7).

Figure 7


Between Bussman junction block and main circuit breakers’ bus bar (Figure 8).

Figure 9: Power cable on main
circuit breakers' bus bar.

Figure 8

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PROCEDURE
DANGER
Park vehicle safely, apply parking brake, stop engine. Prior to working on the vehicle, set the ignition
switch to the OFF position and trip the main circuit breakers equipped with a trip button. On Commuter
type vehicles, set the battery master switch (master cut-out) to the OFF position.

POWER CABLES GENERAL INSPECTION CRITERIA
1. Make sure that the power cables are properly secured with appropriate fasteners so that they
do not move. Movement of the cables can cause wear of the extruded protective sheath,
strains on stud terminals and ring cable lugs.
2. Ensure that the power cables do not rub on other cables or other components.
3. Make sure ring cable lugs are securely attached to the stud terminals, that the retaining nut is
tightened. Also, make sure that cable lug crimping holds firmly on copper conductor.

OTHER THINGS TO CHECK


Check for damages caused by electric arcs with loss of material along the copper conductor.



Check for damaged cable extruded sheath and having lost its insulating properties.



Bosch T1 alternator: ensure that the rubber grommets at the rear cap of the alternator are present.



P-clamp type cable clamps must be suitable for cable diameter. The cable must remain in the P-clamp
without moving or rubbing, thus oversized P-clamps are not allowed. Inspect the corrugated protective
sheath passing through the P-clamp for signs of wear.



At certain locations, power cables are protected by a corrugated protective sheath and should remain
as such.

Figure 10: starter cables in a corrugated protective sheath.


Ensure that the power cables do not rub on bolt heads or sharp metal edges that can cut or wear the
cable extruded sheath.



For power cables passing through a corrugated protective sheath, it is recommended to apply two
layers of fabric tape every 3 to 6 inches minimum to prevent the cable from coming out of the

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corrugated protective sheath (Figure 11). The ends of the corrugated protective sheath should be
covered with fabric tape (Figure 12).

Figure 11: Two layers of fabric tape applied every 3
to 6 inches to prevent the cable from coming out of
the corrugated protective sheath.


Figure 12: The ends of the corrugated protective
sheath should be covered with fabric tape.

Stud terminal nuts properly tightened. Use a nut with nylon insert to replace a similar nut where
applicable. Protect ring cable lugs against tightening force by placing a flat washer between nut and
ring cable lug.

When necessary, use fasteners that secure cables while preventing rubbing

RING CABLE LUGS

Figure 13: Cable lugs must be closed type, crimped or welded.


Ring cable lugs should not be distorted.



Ring cable lugs should not suffer strains that can deform.

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

Ring cable lugs must be installed with smooth washers and nuts to prevent damage to the cable lug
when tightening.

Figure 14: Power cable shouldn’t be bent just next to the cable lug. Angled cable lugs are used to avoid
mechanical stress.

Figure 15: When several terminals are connected on a single stud terminal, the largest cable lug must be
placed first, followed by the second larger and so on. Cable lugs should be distributed around the stud
terminal in a way that no cable lug is distorted when tightening the nut.

Figure 16: No exposed or broken copper strands.


A shrink tubing (or fabric tape) should cover the copper strands.



Ensure that the power cables and ground wire are not stretched tight.



Ensure that the cable lugs are still properly crimped on the copper conductor, that the conductor
strands are not broken so that the power cable retain its capacity and ensure unrestricted current flow.

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BATTERY CABLES


Battery interconnection cables must be checked too :

‒

Ensure the cables are properly fastened to battery posts and that the cables are in good condition
(consult battery manufacturer documentation for appropriate tightening torque).

‒

No corroded or cut copper strands. No apparent copper strands. Protective sheath in good condition,
no cuts, no rubbing against metal edges.

Figure 17: battery bank

STEEL P-CLAMPS

Figure 18: P-clamps are no longer used to secure power cables, but they can nevertheless be found on
coaches of older generations. The piece of rubber that protects cable against the P-clamp steel loop must
absolutely be in place. Replace any P-clamps where the rubber piece is missing, broken or likely to
separate from the steel loop.

NOTE
Unlike steel P-clamps, plastic clamps have the advantage of being not conductive. A good practice
would be to replace P-clamps securing power cables with appropriate nylon cable ties like the
following:
#507664 CABLE TIE, DOUBLE LOOP
#509491 CABLE TIE, WIDE

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Figure 19: P-clamp with appropriate diameter prevents the power cable or corrugated protective sheath
from moving and rubbing inside the clamp.

ALTERNATORS
TERMINAL NUT PRESCRIBED TORQUE

Bosch HD10
- B1(+) terminal: 10 lbf-ft
- ground: 6 lbf-ft
Bosch T1
- D+: 21-28 lbf-in
- B+, B-: 88-115 lbf-in
- W: 36-48 lbf-in
Delco 50DN
- DC Output: 30-35 lbf-ft
- F1, F2, Relay: 6 lbf-ft
Figure 20: Make sure power cables/positive cables (+) are
properly connected to alternator, that stud terminal nuts are
properly tightened.

Figure 21: Bosch T1 alternator with the two
required rubber grommets. Alternator cables
connected to the alternator stud terminals must be
protected against metal edges with rubber
grommets.

Figure 22: Fire in engine compartment caused by
rubbing of power cable against metal edge of
Bosch T1 alternator rear cover. Lower rubber
grommet was missing when fire occured.
Evidence of electrical arc can be seen.

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CORROSION PROTECTION


Power cable connections on alternators, starter and ground connections exposed to water, dust, etc.
should be protected against corrosion with Loctite Color Guard rubber coating (Figure 23) (Prevost
p/n: 684013).

Figure 23: Loctite Color Guard.

Figure 24: Upper alternator power cable lug
protected with Color Guard rubber coating.

Figure 25: Lower alternator power cable lug
protected with Color Guard rubber coating.

Figure 26: Starter power cable and ground cable
lugs protected with Color Guard rubber coating.

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PARTS / WASTE DISPOSAL
Discard according to applicable environmental regulations (Municipal/State[Prov.]/ Federal)

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