Field reference for EV charging technicians. 24 entries, taken from the PlugWatt app.
Reference notes from PlugWatt, the offline field toolkit for electric vehicle charging installation and service technicians. It works with no cell signal, because the sites do not have any.
Get PlugWatt on the App StoreLarge public and fleet network; Express series DC fast chargers plus widespread Level 2.
name: Express 250. powerRange: 62.5 kW per cabinet, paired to 125 kW. notes: Modular Power Blocks feed dispensers; power sharing across paired units.
name: Express Plus. powerRange: Up to 500 kW architecture. notes: Power Blocks and Power Link cabinets feeding Express Plus dispensers.
name: CPF and CT4000 family. powerRange: Level 2 AC. notes: Common workplace and public AC units.
Dispenser Charge Controller (DCC) faults often present as handshake failures; check DCC status LEDs and logs first
Cable and contactor box assemblies are field replaceable units on Express hardware
Network side management runs through ChargePoint cloud; offline behavior follows operator policy
Terra family DC fast chargers from 24 kW wallboxes to 350 kW high power cabinets.
name: Terra 54. powerRange: 50 kW. notes: Workhorse corridor unit; CCS plus CHAdeMO variants common.
name: Terra 124 and 184. powerRange: 120 to 180 kW. notes: Modular power stacks; dual simultaneous outputs on many builds.
name: Terra HP. powerRange: 175 to 350 kW. notes: Liquid cooled cables; separate power cabinet and dispenser.
Isolation monitoring trips are a common Terra service call; moisture in glands and conduit is the usual find
Power modules are hot swap by procedure on larger Terra models
Terra HP liquid cooled cable loops need coolant checks on PM visits
The charger detected DC residual current leaking to ground above 6 mA. On a Level 2 unit this is the DC leakage detection required so that an upstream AC residual current device is not blinded by DC.
Treat it as a real leakage path until proven otherwise rather than resetting to see whether it clears
Check the vehicle first by trying a different EV, since a failing on board charger is a common source of DC leakage and the charger is reporting correctly
Check for moisture in the enclosure, the cable gland and the connector, which is the usual cause after weather
Inspect the output cable for damage where it is driven over or pulled
Check the connector pins for corrosion or debris bridging to earth
If it repeats on multiple vehicles the fault is the charger side; escalate rather than resetting repeatedly
AC residual current above 30 mA leaking to ground. Same family as the DC detection but on the AC side, and the threshold where personnel protection acts.
Treat as a live earth fault and do not reset repeatedly
Try a different vehicle to separate the EV from the charger
Check for water ingress at the enclosure, gland and connector
Inspect the output cable along its full length for damage
Check the AC supply wiring and terminations inside the unit for a conductor touching earth
Check whether it correlates with rain or wash down, which points at ingress rather than electronics
The residual current monitor failed its own self test, so the protection cannot be relied on. The unit is reporting that its safety device is not trustworthy.
Take the unit out of service, because personnel protection is what is reporting faulty
Power cycle once to rule out a transient self test failure
Check the monitor module connections and its wiring
Do not disable or bypass the monitor to keep the charger earning
Replace the monitor if the self test keeps failing, and retest before returning to service
A relay contact is overheated or damaged and is not behaving as commanded. A welded relay means the output may stay energised when the charger believes it is off.
Treat the output as potentially live regardless of what the unit indicates
Isolate and verify absence of voltage before touching the output
Inspect the relay for heat damage, discoloration and pitting
Establish what damaged it, because closing into a fault or a high resistance connection will destroy the replacement the same way
Check the output cable and connector for a fault that caused the overload
Replace the relay rather than attempting to clean or reuse it
The unit is not earthed correctly. Everything protective on a charger depends on a solid earth reference, so nothing else can be trusted while this is present.
Take the unit out of service; without earth the protection functions cannot work
Check the earth conductor termination at the charger
Check earth continuity back to the panel, measuring rather than looking
Check the earth connection at the supply end and at any junction in between
Check for a corroded or loose earth lug, which is the common failure outdoors
Do not return the unit to service until earth continuity is proven
Line and neutral are reversed on the AC input. The unit works out that the supply is wired the wrong way round.
Isolate before touching anything, since the wiring is by definition not what the labels say
Confirm the reversal at the charger terminals with a meter rather than trusting colours
Trace back to the supplying breaker, because the error is usually made at the panel or a junction
Correct the wiring and verify polarity at the charger before re energising
Check any other outlets or equipment on the same circuit, since a reversal usually affects more than one thing
A phase is missing or reversed on the supply. On a three phase unit that means it cannot deliver rated output and may not start at all.
Check the supply breaker, since a single pole tripped on a three phase breaker is the usual cause
Measure all three phases at the charger input rather than at the panel
Check for a blown fuse on one phase
Check phase rotation if the unit reports reversal rather than absence
Check terminations at the charger and at the panel for a loose or burnt conductor
Look for a utility side issue if all three are low or one is absent at the service
There is an overload on the vehicle side. The charger is limiting because the EV is drawing more than the session allows.
Check whether it happens with one vehicle or several, because one vehicle points at that EV's on board charger
Check the configured maximum current against the cable rating and the circuit
Check the vehicle's own charge settings, since some EVs allow a current limit to be set on board
Check the connector and cable for heat damage, which both causes and results from overcurrent
Do not raise the current limit to stop the alarm
Charging current is too high for the conditions and the unit is protecting itself. Thermal management on a charger is mostly airflow and connection quality.
Check the connector and cable for heat damage first, because a high resistance connection generates heat exactly where this trips
Check the ambient temperature and whether the unit is in direct sun
Check ventilation openings and any filter for blockage
Check the terminations inside the unit for a loose connection, which heats under load
Check whether it derates at the same time each day, which points at ambient rather than a fault
Let it cool and retest under load rather than assuming the reset fixed it
The attached cable is rated below the device's rated current. The charger is refusing to deliver more than the cable can carry, which is correct behaviour.
Check the cable rating against the unit's configured output
Check whether the cable was replaced with a lower rated assembly
Check the proximity pilot resistor, since that is how the cable declares its rating and a wrong or damaged resistor misreports it
Fit the correct cable rather than raising the configured current
Inspect the connector for damage that may have altered the proximity circuit
Internal boards are not communicating with each other. This is inside the unit rather than out on the installation.
Power cycle once, since a single internal comm fault is often transient
Check internal ribbon and harness connections are seated, especially after any service work
Check for moisture or corrosion inside the enclosure
Check firmware versions across the boards if any were replaced
Escalate to ABB rather than swapping boards speculatively
Supply voltage above the permitted window. The charger stops rather than passing it to the vehicle.
Measure the supply voltage at the charger input under load, not at rest
Check whether other equipment on the same supply is also seeing high voltage, which points upstream
Check the neutral connection, since a poor neutral produces high voltage on one leg and low on another
Check transformer tap settings if the site is consistently high
Contact the utility if the supply itself is out of range
Supply voltage below the permitted window, which the charger will not work through.
Measure at the charger input under load, since voltage drop only shows when current flows
Check the conductor size against the run length, because a long undersized run is the classic cause
Check terminations at both ends for a high resistance joint
Check whether other loads on the circuit pull it down when they start
Check the supply at the panel to separate the branch circuit from the service
Veefil heritage; RTM and PKM families. Distinctive liquid cooled power electronics in a slim IP65 package.
name: RTM75. powerRange: 75 kW. notes: Compact unit; liquid cooled electronics, air cooled cables.
name: PKM150. powerRange: 150 kW. notes: Modular 25 kW power units; scalable site architecture.
name: Veefil RT50. powerRange: 50 kW. notes: Earlier fleet still widely deployed.
Coolant loop service requires the documented bleed procedure; air pockets cause phantom thermal derates
IP65 sealing means enclosure openings must be resealed to specification after service
Older Veefil units may need firmware updates before newer vehicles negotiate cleanly
The charger could not respond to changing grid conditions during a session and stopped regulating within limits.
Return the plug to the charger, which is the documented first step
Perform a remote charger reset rather than a local power cycle
Check whether the site grid is weak or fluctuating at that time of day, since the fault is about responding to grid change
Check whether it recurs with one vehicle or several
Collect the session timestamp before resetting, because the log around it is the diagnosis
Escalate to Tritium with the timestamps if it repeats
The supply left the permitted window: below 432 V or above 528 V, or below 55 Hz or above 65 Hz. Tritium names a short power glitch, three phase loss, an internal RCD trip and an internal breaker trip as causes.
Check the internal RCD and the internal breakers first, because both are listed causes and both are inside the unit
Measure all three phases at the input and compare against 432 V and 528 V
Check frequency if the site has generation or a weak supply
Check whether the utility logged an event at that timestamp, since a short glitch leaves no other trace
Check for a lost phase upstream at the panel
Correlate across other chargers on site, because all of them tripping together is a supply event
The safety system detected the connector being pulled during an active session, outside normal operating parameters. The charger locks itself deliberately.
Do not power cycle and do not press the emergency stop, because Tritium specifically says not to
Do not attempt to clear it locally; the unit stays locked until serviced by design
Contact the station owner to arrange Tritium service
Record what happened before the lock, since a pulled connector under load may have damaged the cable or connector
Inspect the cable and connector for damage while waiting on service
Hypercharger family, 50 kW to 1 MW class, known for power density and high uptime in European and US networks.
name: HYC50. powerRange: 50 kW. notes: Compact wall or pedestal unit.
name: HYC150. powerRange: 150 kW. notes: Two connector dynamic power sharing.
name: HYC300. powerRange: 300 kW. notes: Liquid cooled cables; high utilization corridor unit.
name: HYC1000. powerRange: Up to 1 MW class. notes: Megawatt architecture for trucks and depots.
Dynamic power sharing means one bad module can shave capacity across both connectors
Cable cooling loops on HYC300 class units are PM checklist items
Remote diagnostics through the operator backend resolve many calls without a truck roll
The largest reliable DC network; V2, V3, and V4 posts. NACS (standardized as SAE J3400) opens the connector to other networks and vehicles.
name: Supercharger V2. powerRange: Up to 150 kW paired. notes: Power sharing between paired stalls.
name: Supercharger V3. powerRange: Up to 250 kW. notes: Liquid cooled cables, no stall pairing.
name: Supercharger V4. powerRange: Up to 325 kW and higher. notes: Taller post, longer cable, Magic Dock CCS adapter on some sites, payment terminal on open sites.
NACS uses five pins; the same pair carries AC or DC, so the handshake decides the mode
NACS supports about 19.2 kW AC and 250 kW and more DC on current hardware
Third party vehicles on Superchargers authenticate through Plug and Charge style flows; app account issues look like handshake failures
Magic Dock issues usually present as adapter latch or comm faults
US manufacturer of Level 2 and DC fast equipment common in retail and municipal deployments.
name: Gen 4 DCFC. powerRange: 50 to 200 kW. notes: Modular rectifier shelves; CCS and CHAdeMO options.
name: Level 2 pedestal family. powerRange: AC Level 2. notes: Retail and workplace deployments.
Rectifier shelves are field replaceable; match firmware after swaps
Retail sites often share service transformers; input sag under store load can masquerade as charger faults
Distributed satellite architecture: a power cabinet feeds multiple lightweight dispensers with dynamic power routing.
name: S Series satellite. powerRange: Dispenser fed up to 400 kW. notes: Slim dispensers; cable management arms common.
name: Power Unit C Series. powerRange: 50 to 600 kW cabinet. notes: 25 or 50 kW modules dynamically routed to satellites.
name: Movable model. powerRange: Up to 40 kW. notes: Portable DC unit for depots and events.
Dynamic routing means intermittent faults move between satellites; correlate by timestamp in the cabinet log
Satellite comm cables between cabinet and dispensers are a distinct failure point worth checking early
High power DC fast chargers common in major US charging networks, including 350 kW corridor units.
name: FC100K to FC200K. powerRange: 100 to 200 kW. notes: Dual connector units in retail networks.
name: 350 kW family. powerRange: Up to 350 kW. notes: High power corridor deployments; liquid cooled cables.
name: V2 NACS capable units. powerRange: Up to 400 kW. notes: Newer builds with NACS and CCS options.
Network operator remote diagnostics usually precede a truck roll; arrive with the fault history
High utilization sites benefit from proactive connector and filter PM
Reference notes from PlugWatt, the offline field toolkit for electric vehicle charging installation and service technicians. It works with no cell signal, because the sites do not have any.
Get PlugWatt on the App StoreThese notes are a field aid, not a substitute for the governing codes, the stamped drawings, the authority having jurisdiction, or manufacturer manuals. Verify against the current documentation for your installed equipment.