EV Charger Testing and Commissioning: EVSE Checklist, Earth Loop Impedance and Handover Documentation

Summary

Commissioning an EV chargepoint is more involved than commissioning a standard socket circuit. In addition to the standard IET BS 7671 tests (continuity, insulation resistance, earth loop impedance, RCD), the chargepoint installation has an additional layer: the charging protocol itself. The chargepoint communicates with the vehicle via a control pilot (CP) signal on the IEC 62196 Type 2 connector — this signal must be present and within specification for charging to begin. A functional test with an EV is the definitive confirmation that the installation works.

For OZEV grant installations, the commissioning process also includes connecting the chargepoint to the internet, registering it with the manufacturer's platform, and confirming smart charging functions are active. Grant claims are only processed for connected, smart-capable chargepoints.

Key Facts

• EIC (Electrical Installation Certificate) — required for new circuits (32A dedicated circuit for the chargepoint); must be issued by the installer at handover
• Minor Works Certificate — only acceptable if the chargepoint is connected to an existing circuit (rare for a dedicated 32A install)
• Earth loop impedance (Zs) — measured at the chargepoint terminal; must be within the maximum value for the protective device type and rating; Type B RCBO at 32A typically requires Zs < 1.44Ω
• RCD test — residual current device test: 30mA test current; must trip in ≤300ms (for Type A/F RCDs per BS EN 61008); the chargepoint may contain an integral RCD — test both the RCBO in the consumer unit and any integral RCD in the chargepoint
• Insulation resistance — measured between live conductors and earth; minimum 1MΩ (typically much higher for new cables); disconnect the chargepoint before testing if it contains sensitive electronics
• Polarity — confirm L/N/E are correctly connected at both the consumer unit and chargepoint terminals; reversed polarity on a Type 2 connector can damage vehicle charging electronics
• Control pilot (CP) signal — 12V PWM signal on pin 5 of the Type 2 connector; its duty cycle communicates the available charge current to the vehicle; can be measured with an oscilloscope or EVSE tester
• EVSE tester — a test device that simulates an EV connection; plugs into the Type 2 socket or connects to the tethered cable end; verifies CP signal without needing an actual vehicle present
• Proximity pilot (PP) — pin 4 of Type 2; communicates cable rating to the chargepoint; tested automatically during EVSE function test
• Smart commissioning — connecting the chargepoint to Wi-Fi, registering with the manufacturer cloud platform, and confirming scheduling and demand flexibility functions are active; required for OZEV grant
• CT clamp verification — where load management is fitted, confirm CT readings are correct during a live charge test

Quick Reference Table: EV Chargepoint Commissioning Tests

Detailed Guidance

Pre-Commissioning Checks

Before switching on:

1. Visual inspection — cable entries correctly gasketed; no cable damage; connections tight; no dead ends or loose conductors in the enclosure
2. Trunking/conduit complete — all conduit ends fitted; no exposed cables where mechanical protection is required
3. PME earth treatment — TT electrode installed or PEN detection fitted and configured; do not proceed to testing if the PME earth question is unresolved
4. RCBO/MCB fitted — correct Type B, correct rating; labelled in the consumer unit
5. Cable route confirmed — cable correctly installed, clipped, and protected throughout its route

Electrical Tests

Disconnect the chargepoint electronics before performing insulation resistance and continuity tests. Chargepoint control boards and power electronics are not rated for 500V DC test voltage. Open the chargepoint cover and disconnect the cable cores from the terminals before megger testing. Reconnect before Zs and functional tests.

Continuity and polarity: Use a multifunction tester or low-resistance ohmmeter. Test L–L (ring continuity if applicable), N–N, E–E. Confirm polarity by checking L is on the brown/red conductor through to the correct terminal; N on blue; E on green/yellow.

Insulation resistance: Apply 500V DC between L and E, N and E, L and N. Record values. All should be >1MΩ — in practice, new cable on a short run will read >200MΩ.

Earth loop impedance (Zs): Reconnect chargepoint electronics. Measure Zs at the chargepoint terminal using the multifunction tester's Zs function. The maximum Zs for the protective device must not be exceeded:

• 32A Type B RCBO: Zs max = (80V / Ia) where Ia is the instantaneous trip current; for Type B, Ia = 5 × In = 160A; Zs max = 80/160 = 0.5Ω under UK low-voltage conditions
• Check against the actual tabulated values in the On-Site Guide or IET Wiring Regulations Appendix 3

RCD test: Using a dedicated RCD tester:

1. Set to 30mA test current
2. Apply 0° phase test: RCD must trip in ≤300ms
3. Apply 180° phase test: RCD must trip in ≤300ms
4. Apply 150% (45mA) test: must trip in ≤40ms

If the chargepoint has an integral RCD (many modern chargepoints include one), test it separately using the chargepoint's built-in test button and confirm it trips the circuit.

EVSE Function Test

The control pilot test confirms the chargepoint's communication electronics are working. Using an EVSE tester (available from test equipment suppliers such as Megger, Fluke, or specialist EV test tool manufacturers):

1. Connect the EVSE tester to the Type 2 socket (for untethered chargepoints) or to the tethered cable's vehicle connector
2. The tester simulates a vehicle connection
3. Observe the chargepoint: it should detect the connection and enter "ready to charge" state
4. Confirm the CP signal: 12V idle, transitioning to PWM when the tester simulates a ready vehicle
5. The PWM duty cycle should correspond to the configured maximum charge current (e.g., 32A = 32% duty cycle approximately)
6. Confirm the chargepoint begins simulated charging (EVSE tester confirms current flow)

Functional test with a real EV: Where possible, connect a real EV to confirm end-to-end function. This is the only way to test the vehicle-side communication. Confirm:

• Vehicle accepts the connection without error
• Charging initiates (vehicle dashboard shows charging; current flow confirmed)
• Charge at the correct rate (within 5% of expected kW at the vehicle display)

Smart Commissioning

For OZEV grant installations and any internet-connected chargepoint:

Step 1: Connect to Wi-Fi Follow the chargepoint manufacturer's procedure to connect the chargepoint to the customer's broadband Wi-Fi. Most chargepoints have a WPS button or a temporary Wi-Fi access point for initial setup.

Step 2: Register the chargepoint Create or log into the manufacturer's app/portal using the customer's account. Register the chargepoint serial number. Confirm the chargepoint shows as "Online" in the platform.

Step 3: Configure smart charging schedule Set up the default overnight charging schedule:

• Preferred charge window: midnight to 07:00 (or customer's off-peak tariff window)
• Minimum charge by: 07:00 (configurable target state of charge)
• Demand flexibility: confirm enabled (required for Smart Charge Points Regulations 2021 compliance)

Step 4: Configure load management If a CT clamp is fitted, confirm the CT reading in the app during a background household load test. Set the main fuse rating. Test by running a high-load appliance and observing the chargepoint throttle.

Step 5: Confirm OZEV compliance For grant installations, log into the installer's OZEV portal and submit the installation claim with:

• Chargepoint serial number and model
• Installation address
• EIC number
• Photos of the chargepoint, consumer unit, and completed installation
• Confirmation of smart commissioning

Handover to Customer

The handover pack must include:

• EIC (Electrical Installation Certificate) — signed by the installer; specifies the circuit, protection, test results
• Chargepoint manufacturer documentation — installation manual, warranty card, compliance certificates
• App registration confirmation — customer has the app set up with their login; schedule configured
• Load management settings sheet — if CT clamp fitted; summary of configured fuse rating and minimum charge rate
• Emergency stop / isolation procedure — how to isolate the chargepoint (main switch in consumer unit; chargepoint power button if applicable)
• Customer briefing — modes (eco, eco+, fast if applicable); how to override schedule for a quick charge; how to check charge status

Frequently Asked Questions

Do I need to test with a real EV or is the EVSE tester sufficient?

The EVSE tester is sufficient for confirming the chargepoint function and CP signal. However, testing with a real EV is best practice — it confirms the complete installation from consumer unit through to vehicle. Where a real EV is available (the customer's own vehicle), always perform a live charge test. An EVSE tester is a backup for when no vehicle is available at commissioning time.

What Zs value should I record on the EIC for a 32A Type B RCBO?

Record the measured Zs at the chargepoint terminals. The maximum permissible Zs for a 32A Type B RCBO under the 0.4s disconnection time requirement is given in the IET Wiring Regulations appendix tables — approximately 1.44Ω for a 32A device at the 5× instantaneous trip current. For a well-installed short cable run, measured Zs will typically be 0.1–0.5Ω — well within limits.

The chargepoint won't connect to Wi-Fi. What should I check?

Common causes: customer has 5GHz-only Wi-Fi (most chargepoints require 2.4GHz; confirm the router has 2.4GHz enabled); the chargepoint is too far from the router (signal too weak); the Wi-Fi password was entered incorrectly. Try the WPS button on the router as an alternative. If the chargepoint has a status LED, check the manufacturer's LED codes for Wi-Fi connection state.

Is there a separate commissioning requirement for NAPIT/NICEIC registration?

Where the installer is a registered Part P electrician or registered with an NICEIC/NAPIT scheme, the EIC is self-certified under the competent persons scheme — no separate building control notification is required. The EIC is the certification document. The chargepoint manufacturer may also require the installer to be on their authorised installer list (particularly for OZEV grant claims).

Regulations & Standards

• BS 7671:2018+A2:2022 — Part 6: inspection and testing; Chapter 722: EV chargepoints

• Electric Vehicles (Smart Charge Points) Regulations 2021 (SI 2021/1467) — commissioning requirements for smart functionality

• IET Guidance Note 3 — inspection and testing; relevant test procedures

• IET Guidance Note 7 — EV charging; commissioning checklist

• Building Regulations Part P — notifiable work; self-certification via competent persons scheme

• IET Guidance Note 7 — EV Charging — commissioning guidance

• OZEV Approved Installer Portal — grant claim documentation requirements

• IET Wiring Regulations 18th Edition (BS 7671:2018+A2:2022) — Chapter 722 and Part 6

• ev charger installation types — chargepoint hardware types and circuit design

• bs 7671 ev wiring requirements — Chapter 722 circuit design and protection

• pme earthing ev charging — earthing verification at commissioning

• ct clamp load management — CT clamp commissioning and verification

• ozev approved installer — OZEV grant claims and installer registration