US/Canada: the smaller blade is hot (right outlet slot). UK: brown wire to “L”. Australia: left pin is active with earth down.
Which Side Is Hot On A Plug In Each Region
Polarity is the match up between hot (live), neutral, and earth/ground. On the plug, the hot side is the connection that brings power into the device. On the outlet, it’s the slot or pin that feeds that same hot conductor. Here’s a quick map before the deeper walk-through.
| Region / System | Hot Side On Plug/Outlet | Notes |
|---|---|---|
| US & Canada (NEMA 1-15 / 5-15) | Smaller blade is hot; on a wall outlet, the right slot is hot with the ground hole below | Neutral blade/slot is wider to keep polarity |
| UK & Ireland (BS 1363) | Brown wire to “L” terminal; looking at the plug front, the lower right pin is live | Top pin is earth; plug contains a fuse |
| Australia & New Zealand (AS/NZS 3112) | With earth down, the upper left pin is active (hot) | Upper right pin is neutral |
| Most of Europe (Type E/F, Schuko) | No fixed hot side on many sockets; plug can be inserted either way | Polarity depends on socket wiring |
North America: Identifying The Hot Side
On polarized two-blade plugs, the narrow blade is hot and the wide blade is neutral. On three-blade plugs, the round pin is ground, the narrow blade stays hot, and the wide blade stays neutral. Facing a standard duplex outlet with the ground hole at the bottom, the right slot is the hot feed and the left slot is neutral.
When you wire a replacement plug, the brass-colored screw ties to the hot blade and the silver screw ties to the neutral blade. Many lamp cords also mark the neutral conductor with fine ribs on the insulation; the smooth side is hot. This keeps the outer threads of a lamp socket at neutral and runs the switch only on the hot conductor.
Want a quick reference? The National Electrical Manufacturers Association documents polarized blades, and the NEMA connector overview explains the wider neutral blade and the narrow hot blade used on North American plugs.
Two-Prong Vs. Three-Prong
Two-prong polarized cords keep hot and neutral aligned but lack a path to ground. Three-prong cords add a ground pin to clear fault current. Both follow the same narrow-is-hot rule, and both mate with the same 15-amp receptacles found in homes.
Common Mistakes To Avoid
- Don’t file a blade or remove the ground pin to “make it fit.” That defeats polarization and can leave exposed metal live.
- Don’t move the white neutral to the brass screw on a replacement plug. White goes to silver; black (or red) goes to brass; green goes to the green ground screw.
- If an outlet is old and both slots are the same size, treat it as unpolarized and plan an upgrade.
United Kingdom & Ireland: Which Pin Is Live On A BS 1363 Plug
Inside the BS 1363 plug body, the brown wire lands on the terminal marked “L” (live), the blue wire lands on “N” (neutral), and the green/yellow lands on the earth terminal. With the plug pins facing you and the earth pin at the top, live is the lower right pin. The Electrical Safety First guide shows the color code and the role of the fuse in the plug.
Fused Plug And Shuttered Socket
The BS 1363 plug carries a replaceable cartridge fuse sited on the live side. The socket uses shutters that open only after the earth pin engages. Both features pair with correct polarity: live enters through the fuse, neutral returns on the other side, and the earth connection makes contact first.
Quick Wiring Tips
- Brown to “L,” blue to “N,” green/yellow to the earth terminal.
- Trim the cores so the earth is longest, neutral medium, live shortest; that way a hard yank tends to pull live first, then neutral, with earth last.
- Pick the correct cartridge fuse for the appliance rating, and seat it firmly.
Australia & New Zealand: Active, Neutral, Earth
The AS/NZS 3112 plug has two flat pins in a “V” and a vertical earth pin. Viewed from the front with the earth down, the upper left pin is active (hot) and the upper right pin is neutral. The Electrical Equipment Safety System note shows the pin order as earth, neutral, active in clockwise sequence when viewed from the pin side.
Cable Colors Under AS/NZS Rules
Modern flexible cords use brown for active, blue for neutral, and green/yellow for earth. If a cord looks older and colors don’t match, replace the cord or fit a new lead that follows current markings.
What Side Of A Plug Is Hot On Common European Sockets
Type E/F (“Schuko”) sockets across much of Europe accept round-pin plugs that can be inserted either way. That means hot and neutral may swap depending on the socket. Many appliances shipped with these plugs are built to accept either orientation without issue. Travel adapters that convert between systems may present a fixed live on their outlet face, yet the wall socket upstream can still feed either contact as line or neutral.
Safe Use With Adapters
Bring a fused adapter from a known brand. Watch the total current draw on multi-way adapters, leave space around plugs so they don’t overheat, and don’t chain travel cubes or stacks.
How To Tell Hot From Neutral On A Cord Or Plug
When markings aren’t obvious, these quick checks help:
- Screw colors: Brass = hot; silver = neutral; green = ground.
- Blade size: Narrow blade = hot; wide blade = neutral (North America).
- Insulation feel: Smooth side on a two-wire lamp cord = hot; ribbed side = neutral.
- Stamping: Look for “L” and “N” near terminals; “E” or the ⏚ symbol marks earth.
- Fuse location: On UK plugs, the fuse sits on the live side beside the “L” terminal.
Table Of Quick Checks And Fixes
| What You See | What It Means | What To Do |
|---|---|---|
| Wide and narrow blades on a two-prong plug | Polarized cord; narrow is hot | Match narrow blade to the right slot on the outlet |
| Silver and brass screws on a replacement plug | Polarity markers | White to silver, black to brass, green to ground |
| Schuko plug and socket | No fixed hot side | Use gear rated for either orientation |
| UK plug with fuse next to a terminal | That terminal is live | Brown wire to the fused “L” side |
| Australian plug with earth down | Upper left pin is active | Brown to left pin, blue to right |
Step-By-Step: Wire A Rewirable Plug Safely
- Unplug the device and open the plug housing.
- Trim the cord jacket so the clamp grips it, not the inner conductors.
- Strip each conductor just enough to fit fully under the terminal.
- Land neutral on the silver “N,” hot on the brass “L,” and ground on the green screw or earth symbol.
- Tighten the terminals. Tug each wire to confirm it’s secure.
- Form a gentle loop so the earth lead is last to pull if the cord gets yanked.
- Re-fit the strain relief and close the housing.
Troubleshooting Polarity Problems
Lights flicker when you jiggle the cord? Outlet tester shows reversed polarity? Here are steps that solve most home cases:
- Swap the two blades on a rewirable two-prong plug if they were wired backward.
- Replace worn or heat-marked plugs and cords rather than patching them.
- Upgrade unpolarized or cracked outlets to modern tamper-resistant, grounded receptacles.
- On a lamp, check that the center tab ties to the switch and the shell ties to neutral.
Polarity Basics For Travelers
Check both ends of any setup. A travel adapter might present a neat, polarized outlet on its face while feeding from an unpolarized Schuko socket in the wall. Pack a small plug-in tester for US outlets at your destination, keep wattage within the adapter’s rating, and replace any adapter that runs hot to the touch.
Final Tips
Match hot to hot and neutral to neutral. Use the markings on plugs, the blade widths, and the cord ridges to spot the hot side fast. When something looks odd, check a wiring diagram for your plug type and replace damaged parts with listed components that match your region. For a color-code refresher, the Electrical Safety First page is handy, and for Australia the EESS guidance covers AS/NZS 3112 details.