By WCED
3-Phase PEN Fault Protection Unit – PME/TN-C-S EV Charger Safety | Tesla Compatible
£185.00 - £355.00
Regular price
£305.00
Regular price
Sale price
£305.00
Unit price
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Supplied and supported by Eco Harmony — your trusted UK specialist for EV charging and electrical protection.
1-Year Warranty
Fast UK Shipping
Single & Three Phase
IP40 & IP65 Rated
Hugely Customisable
SKU:
WMTP28-WER40CSP
The 3-phase PEN fault detection unit with Type 2 surge protection is designed for EV charger installations on PME (TN-C-S) supplies where the charger draws power across all three phases. Available in three configurations, it can protect 2 three-phase chargers, 3 three-phase chargers, or up to 6 single-phase chargers from a single unit — making it equally suited to domestic three-phase installs and commercial multi-bay EV charging. It continuously monitors the supply voltage and automatically disconnects all connected chargers within 5 seconds if a PEN fault is detected.
Tesla Wall Connector (Gen 3) does not include built-in PEN fault detection. On a PME supply, a separate PEN fault detection device is required by BS 7671:2018 Amendment 2 for a compliant outdoor installation. This unit has been used by UK installers specifically for this purpose and is fully compatible with the Tesla Wall Connector.
Do I need this? If your property is on a PME/TN-C-S supply (the most common supply type in the UK) and you are installing a 3-phase EV charger outdoors, yes — BS 7671 Regulation 722.411.4.1 requires either an earth rod measuring 15 Ω or below, or a PEN fault detection device. This unit replaces the need for an earth rod.
Available configurations
- 2 × 3-phase chargers — 2 × 40 A RCBOs, ideal for dual 11 kW or 22 kW bays
- 3 × 3-phase chargers — 3 × 40 A RCBOs, ideal for small commercial multi-bay installs
- 6 × single-phase chargers — 6 × 40 A RCBOs, ideal for single-phase charger banks fed from a 3-phase supply
All variants include a single shared PEN fault detection module and Type 2 surge protection device, protecting all connected charger circuits from one enclosure.
What's included in this unit
- PEN fault detection module — monitors all three phases continuously
- 40 A RCBOs — one per charger circuit (2, 3, or 6 depending on variant)
- Type 2 surge protection device (SPD) — guards against transient overvoltages from lightning and grid switching events
- Fitted enclosure, DIN rail mounted, ready to wire
Technical specifications
| Specification | Detail |
|---|---|
| Supply type | 3-phase TN-C-S (PME) |
| Variants | 2 × 3-phase chargers / 3 × 3-phase chargers / 6 × single-phase chargers |
| RCBO rating | 40 A, Type A — one per charger circuit |
| Surge protection | Type 2 SPD (shared across all circuits) |
| PEN fault disconnect voltage | <207 V or >253 V (±10% of 230 V nominal) |
| Disconnect time | Within 5 seconds |
| Mounting | 35 mm DIN rail |
| Regulation compliance | BS 7671:2018 Amendment 2, Reg 722.411.4.1 |
| Compatible chargers | Tesla Wall Connector (Gen 3), Hypervolt, Easee, and other 3-phase and single-phase AC chargers |
Who this is for
- Installers fitting 2 or 3 three-phase EV chargers (11 kW / 22 kW) from a single 3-phase supply
- Commercial installs with up to 6 single-phase EV charger bays fed from 3-phase
- Installers of Tesla Wall Connectors who need compliant PEN fault protection
- Domestic and commercial installs where an earth rod is impractical or undesirable
- Any outdoor 3-phase EV charger installation requiring BS 7671 Amendment 2 compliance
Frequently asked questions
Does the Tesla Wall Connector have built-in PEN fault detection?
No. The Tesla Wall Connector Gen 3 (the current UK model) does not include built-in PEN fault detection. BS 7671 Amendment 2 requires that EV chargers on PME supplies either use a TT earthing system with an earth rod or be fitted with an external PEN fault detection device. This unit satisfies that requirement and is compatible with the Tesla Wall Connector.
Can this unit replace an earth rod on a PME supply?
Yes. A compliant PEN fault detection device is a recognised alternative to an earth rod under BS 7671 Amendment 2. It monitors the voltage continuously and disconnects the charger within 5 seconds if it detects a condition consistent with an open PEN conductor — typically a voltage outside the 207–253 V range.
What is the difference between PEN fault detection and surge protection?
They protect against different risks. PEN fault detection monitors for a broken or disconnected neutral/earth conductor (a PEN fault), which can cause the vehicle chassis to become live. Surge protection (Type 2 SPD) diverts transient overvoltages — from lightning or grid switching — safely to earth before they can damage the charger's electronics. This unit includes both in a single enclosure.
Do I need a 3-phase unit or a single-phase unit?
If your supply is 3-phase, you need a 3-phase PEN fault detection unit regardless of whether the chargers themselves are 3-phase or single-phase. This unit is available in three variants: protecting 2 or 3 three-phase chargers (11 kW / 22 kW each), or up to 6 single-phase chargers (e.g. 7 kW each) all fed from the same 3-phase supply. For a single 7 kW single-phase charger on a single-phase PME supply, see our single-phase PEN fault detection unit.
Is my property on a PME supply?
Most UK properties are. A PME (TN-C-S) supply has a combined earth and neutral conductor running from the substation. You can often identify it at your meter or consumer unit — the earth terminal is connected to the neutral/supply cable rather than running to a separate earth rod. If you are unsure, your installer can confirm the earthing arrangement before specifying the protection devices.
Is surge protection mandatory under BS 7671 Amendment 2?
BS 7671 Amendment 2 requires a risk assessment for surge protection on EV charger installations. In practice, the vast majority of UK installers include Type 2 surge protection as standard — the risk assessment almost always concludes it is required, and it protects the charger's sensitive electronics from transient overvoltages caused by lightning and grid switching.
Related products and resources
Single-phase PEN + Surge unit
Single-phase PEN detection only
Product Finder
PME FAQs
Understanding PEN Protection
Installer Guide
BS 7671 Compliant
PME / TN-C-S
3-Phase
Tesla Compatible
Up to 6 Chargers
No Earth Rod Needed
Type 2 Surge Protection
40A RCBOs
Commercial & Domestic
UK Stock
Regular price
£305.00
Regular price
Sale price
£305.00