The cable listing says “7kW single-phase” or “22kW three-phase.” The price difference is roughly £20. And you’re standing there wondering whether this matters, or whether you’re about to pay a premium for a spec your car and home can’t actually use. We’ve answered this question for thousands of UK EV owners, and the short version is this: for most UK buyers, a 22kW three-phase cable is the smarter buy, even if your home is single-phase today. Here’s why.
What the power rating on a cable actually means
When a cable is listed as “7kW” or “22kW,” that number describes the maximum power the cable can carry, not the power it always delivers. The actual power you get depends on three things acting together: the cable’s rating, the charger or post’s output, and your car’s onboard AC charger limit.
Power in an EV charging cable is the product of voltage, current, and the number of phases. A single-phase 32A circuit at 230V delivers 230 × 32 = 7,360 watts, or roughly 7.4kW. A three-phase 32A circuit at 400V (line-to-line) delivers √3 × 400 × 32 = 22,170 watts, or roughly 22kW. The formula underpins the two cable tiers, and it’s anchored in BS 7671:2018+A2:2022 (IET Wiring Regulations), Section 722, which governs EV charging circuits.
- Bar chart with 4 bars: (1) Single-phase 16A = 3.7kW, (2) Single-phase 32A = 7.4kW, (3) Three-phase 16A = 11kW, (4) Three-phase 32A = 22kW. X-axis: cable/supply combination. Y-axis: Power (kW). Annotate typical use: most UK homes on 7.4kW bar; public 11kW post on 11kW bar; 22kW destination charger on 22kW bar.
The cable rating is therefore a ceiling, not a guarantee. A 7kW single-phase cable will never deliver more than 7.4kW no matter what it’s plugged into. A 22kW three-phase cable can deliver up to 22kW, but only if the post and the car’s onboard charger both allow it. If you want to know what charging speed to expect for your specific car, our guide on how fast your EV will actually charge runs through onboard charger limits by model.
Single-phase vs three-phase: the real difference in the cable
The pin count is the physical marker. IEC 62196-2, the AC connector standard defining the Type 2 format, specifies two variants:
- 5-pin Type 2 (single-phase): L1 (one live phase), N (neutral), PE (protective earth), CP (control pilot), PP (proximity pilot). This cable carries one live current-carrying conductor.
- 7-pin Type 2 (three-phase): Adds L2 and L3, the second and third live phases. This cable carries three live current-carrying conductors.
Both use the same external Type 2 connector housing. The car-side connector is identical regardless of which variant you hold. From the outside, you cannot tell a 5-pin from a 7-pin cable by looking at the car end alone. You need to examine the wallbox/post plug, where the two extra pins are visible as additional holes.
- 5-pin single-phase layout: L1 (top-left), N (top-right), PE (top-centre), CP (bottom-left), PP (bottom-right). 7-pin three-phase adds L2 (mid-left) and L3 (mid-right). Both share identical external Type 2 housing. Label both diagrams side-by-side, titled Single-phase (7kW) with 5 pins and Three-phase (22kW) with 7 pins.
Almost every UK home is single-phase. Only around 3-5% of UK residential properties have a three-phase supply: typically rural properties, farms, large new-builds, or converted commercial premises. For most readers, the question isn’t “can I charge at 22kW at home?” (the answer is almost certainly no). The question is: “which cable should I carry?” And that’s a different question, with a different answer.
For a deeper dive into what single- and three-phase supply means for your property and your charging options, see our guide on single-phase vs three-phase EV charging.
The backward-compatibility fact that changes everything
A 22kW three-phase Type 2 cable plugs directly into a single-phase 7kW wallbox and charges at 7.4kW, exactly as normal.
This is the most important thing to understand, and the detail that competitors rarely explain clearly. When a three-phase cable connects to a single-phase charger, only the L1, N, and PE pins carry current. The L2 and L3 conductors simply sit there, unused, carrying nothing. The wallbox control pilot (CP) handshake, governed by IEC 61851-1, manages the session without caring that L2 and L3 exist.
The reverse is not true. A single-phase 5-pin cable cannot deliver three-phase power because it physically lacks the L2 and L3 pins. Plug a single-phase cable into a 22kW three-phase post and you will charge at 7.4kW maximum, leaving two-thirds of the post’s capacity entirely unused.
This backward-compatibility means the £20 premium for a three-phase cable buys you genuine flexibility:
- At home on your 7kW single-phase wallbox: 7.4kW, the same as a 7kW cable.
- At a public 11kW AC post: up to 11kW (with a compatible car). A 7kW cable caps you at 7.4kW here.
- At a public 22kW AC post: up to 22kW (with a 22kW-capable car). A 7kW cable caps you at 7.4kW here.
That flexibility is the entire case for the 22kW cable for the vast majority of UK buyers who will never have three-phase at home.
Which cars can actually accept 11kW or 22kW AC charging?
Most UK EVs have onboard AC chargers rated at either 7.4kW or 11kW. A small number accept 22kW. The onboard charger is the component inside the car that converts AC grid power to DC for the battery. Its rating is an absolute ceiling that no cable, charger, or public post can exceed.
- Table cols: Model | Max AC onboard (kW) | Benefit from 22kW cable?. Rows: Tesla Model 3 (11kW, Yes, unlocks 11kW at 11kW posts), Tesla Model Y (11kW, Yes, unlocks 11kW at 11kW posts), VW ID.4 (11kW, Yes), Kia EV6 (11kW, Yes), Hyundai Ioniq 5 (11kW, Yes), BMW i3 (11kW, Yes; note: Type 2 inlet, not Type 1), Polestar 4 (22kW select variants, Yes, full speed), Nissan Leaf 40kWh (6.6kW, Partial; cable supports higher posts but car limits speed), Nissan Leaf 62kWh (6.6kW, Partial), Renault Zoe R135 (22kW, Yes, full speed), Audi Q8 e-tron (22kW, Yes, full speed), Smart EQ ForTwo (22kW, Yes).
A note on a common error worth correcting: the BMW i3 is a Type 2 vehicle, not Type 1. Many online guides wrongly list it alongside older Type 1 imports. The i3 uses a standard Type 2 inlet and (depending on variant) has an 11kW onboard AC charger, meaning a 22kW cable does benefit i3 owners at 11kW public posts. For verified onboard charger specs per model, the best source is the manufacturer’s own specification sheet (what we refer to internally as our manufacturer onboard-charger spec cross-reference, S012).
The pattern in the table above is clear: even if your car can’t do 22kW, a three-phase cable still unlocks 11kW at 11kW public posts, for the Teslas, VWs, Kias, Hyundais, and many others. That’s a meaningful speed increase over the 7.4kW ceiling a single-phase cable imposes.
The public AC charger case for a 22kW cable
Public AC destination chargers rated at 11kW and 22kW are becoming the norm at UK hotels, supermarkets, car parks, and leisure destinations. These untethered posts require you to bring your own cable. If you arrive with a single-phase cable, you are hard-limited to 7.4kW regardless of what the post could deliver.
Bring a three-phase cable and your car’s onboard charger determines the speed, which for most modern EVs means 11kW instead of 7.4kW. That translates to roughly 50% faster charging at destination posts: a meaningful difference on a long day out or an overnight hotel stop.
This public-charging use case is why we recommend a 22kW cable even to EV owners who have never seen a three-phase supply and never expect to. The cable is a once-bought travel companion for your car, not just a conduit for your specific home setup.
To fully understand how cable choice and charger type interact with charging speed, our article on which EV charging cable you need covers the complete decision.
The cost and weight trade-off
The price difference between a 7kW single-phase cable and a 22kW three-phase cable of the same length and quality is typically around £20. This is worth keeping in perspective: it is not the cost of three-phase electricity at home (which requires a DNO upgrade and can run from £3,500 to £15,000 depending on the proximity of your nearest three-phase network connection). It is simply the cost of two extra copper conductors in the cable.
The weight difference is real but modest. Three-phase cables carry two additional live conductors, so a 7m three-phase cable is marginally heavier and thicker in cross-section than a 7m single-phase cable of the same current rating. In practice, the difference is a few hundred grams: noticeable if you’re comparing the two in hand, invisible once either is coiled in your boot. For anyone weighing this up alongside their choice of length, our EV cable length guide covers the weight-per-metre picture in detail.
In our own stock and returns data, the dominant reason people replace a cable early is loss or accidental damage, not specification regret. But when specification regret does appear, it almost always runs one direction: buyers who chose the single-phase cable and later found themselves at an 11kW or 22kW post carrying the wrong tool. We’ve never seen someone wish they hadn’t spent the extra £20.
Our recommendation for UK buyers in 2026
Buy the 22kW three-phase cable. Here is the rule of thumb we give every customer:
- If your home is single-phase (almost certainly): the 22kW cable works identically to the 7kW cable at home.
- If you ever use public AC destination chargers: the 22kW cable unlocks faster charging at 11kW and 22kW posts.
- If you ever move home or your supplier upgrades your supply: the 22kW cable is already correct.
- The cost difference is ~£20. The regret potential of buying the 7kW cable is real. The regret potential of buying the 22kW cable is essentially zero.
The only buyer for whom a 7kW single-phase cable is the right choice is someone who charges exclusively at home on a 7kW wallbox, never uses untethered public AC posts, and is certain they will never change either condition. That is a narrow profile.
For anyone uncertain, the broader decision framework, covering connector type, cable length, and power class together, is in our guide on choosing the right EV charging cable.
Frequently asked questions
Does a 22kW cable fit on a 7kW home charger?
Yes. A 22kW three-phase Type 2 cable plugs into any single-phase Type 2 wallbox and charges at the normal 7.4kW rate. The additional phase conductors carry no current. The car-side connector is identical across both cable types, as defined in IEC 62196-2.
Does my home need three-phase electricity to use a 22kW cable?
No. To charge at 22kW, yes, you need a three-phase supply. But the cable itself works fine on single-phase supplies, delivering up to 7.4kW. Only the charger or post, not the cable alone, needs a three-phase supply to reach 22kW.
Which UK cars can charge at 22kW AC?
Very few at full speed: the Renault Zoe R135, certain Audi e-tron and Q8 models, the Smart EQ ForTwo, and selected other models. Most popular UK EVs (Tesla Model 3/Y, VW ID.4, Kia EV6, Hyundai Ioniq 5) cap AC at 11kW. The Nissan Leaf caps at 6.6kW. Even at 11kW, a three-phase cable delivers faster charging than a single-phase cable at 11kW public posts.
Is a 22kW cable physically heavier than a 7kW cable?
Marginally. The three additional conductors (L2, L3, and their insulation) add a small amount of mass. For a 7m cable, the difference is roughly 200-400g: noticeable when you hold both, invisible in daily use.
Will a single-phase cable work on a 22kW public charger?
It will connect, but it will only charge at up to 7.4kW (32A single-phase) regardless of what the post can offer. You cannot unlock 11kW or 22kW speeds with a single-phase 5-pin cable. It lacks the L2 and L3 pins the post needs to deliver three-phase power.
How much more does a 22kW cable cost versus a 7kW cable?
Typically around £20 more for the same length and quality tier. This is the only additional cost, unlike upgrading your home supply to three-phase electricity, which requires a DNO application and costs £3,500-£15,000 depending on your property’s location relative to the nearest three-phase network.
What is the BMW i3 cable type: Type 1 or Type 2?
The BMW i3 uses a Type 2 inlet. It is frequently and incorrectly listed as Type 1 in online guides. All BMW i3 models sold in the UK use the standard Type 2 (IEC 62196-2) connection, with an onboard AC charger capable of up to 11kW on most variants.