USB-C Power Delivery: what the wattage numbers actually mean
April 20, 2026 · Octet team
USB-C is the connector. Power Delivery (PD) is the negotiation protocol. They are not the same thing, and a USB-C cable is not automatically a Power Delivery cable.
Here’s what matters:
USB-C ≠ PD. A USB-C cable can be charge-only, data-only, or both. It can support 60W, 100W, or 240W of charging. It can support 480Mbps, 5Gbps, 10Gbps, 20Gbps, or 40Gbps of data. The connector tells you nothing — the cable spec does.
60W is the default. Any compliant USB-C cable supports up to 60W (3A at 20V) without an e-marker chip. Most cheap cables stop here.
100W requires an e-marker. Power Delivery 3.0 lets a cable advertise itself as 5A-capable through an embedded chip the source and sink can query. Without the e-marker, your 100W charger will negotiate down to 60W and your laptop will charge slowly. The label “100W” on the cable means somebody put the chip in. Or it doesn’t. There is no enforcement.
240W (PD 3.1 EPR) needs a different cable entirely. Extended Power Range goes up to 48V at 5A. Existing 100W cables don’t support 48V — the wires are not rated for the voltage even if they are rated for the current. EPR cables are noticeably thicker and more expensive. They are also rare in the wild.
Data rate is independent. A 240W EPR cable might only support USB 2.0 (480Mbps) for data. A 40Gbps Thunderbolt 4 cable might only deliver 100W. There are no shortcuts — you read the spec sheet.
Practical rules we follow:
- Buy 100W e-marked cables for laptops. 60W charges a MacBook Pro 16” at the same speed your battery drains during a Zoom call.
- Buy 240W cables only for gaming laptops or workstations that genuinely need it.
- Buy short cables for high-data-rate applications. 0.8m TB4 stays passive at 40Gbps. 2m needs to go active and get expensive.
- Label your cables. The 60W charge-only one looks identical to the 100W 40Gbps one. We use a thermal label printer because we got tired of testing.