MAINTENANCE
INFORMATION
DATE :

MAY 2015

SUBJECT :

MI15-24B

SECTION: 06 - Electrical

POWER CABLES INSPECTION GUIDELINES

Revision: B
Added: Power cables for L.H. side alternator & fan drive breaker box
March 25, 2020

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 damage 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 junction block in the electrical
compartment (Figure 1 to 5).

Figure 1 – R.H. SIDE ALTERNATORS (2x BOSCH)
MECHANICAL COOLING FAN DRIVE CONFIGURATION

Figure 2 – L.H. + R.H. SIDE ALTERNATORS (3x BOSCH)
ELECTRIC FAN DRIVE CONFIGURATION

Figure 3 – R.H. + L.H. SIDE ALTERNATORS (2x DelcoRemy)

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Figure 4: Bussman Junction Block - X3 Series.


Figure 5: Bussman Junction Block - H3 Series.

On the starter positive (+) stud terminals and from there, up to Bussman junction block in the
electrical compartment (Figure 6, Figure 7).

Figure 6

Figure 7: starter cables

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

In the electrical compartment, connected to the junction block (Figure 8).

Figure 8



In the battery compartment between battery and master relay R1 (Figure 9).

Figure 9

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

Between Bussman junction block and main circuit breaker bus bar (Figure 10 & Figure 11).

Figure 11: Power cable on main
circuit breakers' bus bar.

Figure 10



From the electric fan drive breaker box up to fuse F199 in main power compartment (Figure 12)

Figure 12: ELECTRIC FAN DRIVE BREAKER BOX

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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 13: 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.

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

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
corrugated protective sheath (Figure 14). The ends of the corrugated protective sheath should be
covered with fabric tape (figure 15).

Figure 14: Two layers of fabric tape applied every 3
to 6 inches to prevent the cable from coming out of
the corrugated protective sheath.


Figure 15: 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 required, use fasteners that secure cables while preventing rubbing

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RING CABLE LUGS

Figure 16: 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.



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

Figure 17: Power cable shouldn’t be bent just next to the cable lug. Angled cable lugs are used to avoid
mechanical stress.

Figure 18: 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.

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Figure 19: 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.

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 20: battery bank

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STEEL P-CLAMPS

Figure 21: 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

Figure 22: P-clamp with appropriate diameter prevents the power cable or corrugated protective sheath
from moving and rubbing inside the clamp.

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ALTERNATORS
TERMINAL NUT PRESCRIBED TORQUE

Delco Remy 55SI
- Ground : 50-60 lb-in
- Positive (+): 80-125 lb-in
- Sense (S) 25-45 lb-in
- Indicator (I) 25-45 lb-in
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
Figure 23: Make sure power cables/positive cables (+) are
properly connected to alternator, that stud terminal nuts are
properly tightened.

Figure 24: 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.

Delco 50DN
- DC Output: 30-35 lbf-ft
- F1, F2, Relay: 6 lbf-ft

Figure 25: 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 26) (Prevost
p/n: 684013).

Figure 26: Loctite Color Guard.

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Figure 27: Upper R.H. side Bosch alternator power
cable lug protected with Color Guard rubber
coating.

Figure 28: Lower R.H. side Bosch alternator power
cable lug protected with Color Guard rubber coating.
Protect the cable lug similarly on the L.H. side
alternator (with electric fan drive)

Figure 29: DELCO REMY ALTERNATOR

Figure 30: 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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Or scan the QR-Code with your smart phone.
E-mail us at technicalpublications_prev@volvo.com and type “ADD” in the subject to receive our warranty bulletins
by e-mail.

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