The amp rating (current-carrying capacity) of a 4mm² cable at 240V depends heavily on how it is installed. In standard domestic or commercial conditions, its capacity typically ranges from 26 to 37 Amps . Quickbit UK +1 Quick Summary of Amp Ratings The way the cable is housed significantly affects its ability to stay cool. If heat cannot escape, the safe amp rating decreases. Quickbit UK +1 Installation Method Rating (Amps) Max Load at 240V Clipped Direct (On a surface, open air) 37A ~8,800 Watts Enclosed in Conduit (Inside a wall) 26A ~6,200 Watts In Free Air (Perforated tray) 41A ~9,800 Watts Thermal Insulation (Surrounded by loft fluff) ~18-23A* ~4,300 Watts *Estimated based on standard derating for thermal insulation; always refer to local regulations like BS 7671 for exact figures. Common Use Cases Radial Socket Circuits: Often used for radial socket runs protected by a 32A breaker. Appliances: Suitable for high-power fixed appliances like
| CSA | Amp rating | Common use | |-----|------------|-------------| | 1.5 mm² | 15–20 A | Lighting | | 2.5 mm² | 24–27 A | Socket rings, 20A radial | | | 32–37 A | 32A radial, small cooker, submains | | 6 mm² | 41–47 A | 40A shower, EV, large cooker | | 10 mm² | 57–64 A | 50A submains | 4mm cable amp rating 240v
If your appliance pulls more than 30 Amps, ensure your installation method allows for heat dissipation. The amp rating (current-carrying capacity) of a 4mm²
4mm cable is a versatile workhorse in the electrical world. At 240V, it comfortably handles loads up to in most domestic scenarios, making it ideal for cookers, garage supplies, and heavy appliances. If heat cannot escape, the safe amp rating decreases
The IET Wiring Regulations (BS 7671) categorize ratings based on how the cable is "clipped" or "buried." Here is how a 4mm² cable performs under different conditions:
(less common at this size): roughly 0.65–0.75× copper rating → ~16–24 A.