FAQ
TL;DR: 85 % of household power-line LAN kits fail once their signal crosses an energy meter [Devolo, 2022]. “Measure 0 V = same phase, about 400 V = different” [Elektroda, Fazi87, post #11276091] Use a 20 m+ extension lead or a multimeter; never bridge phases with a single 230 V bulb.
Why it matters: Wrong phase or a meter filter means zero bandwidth to your basement.
Quick Facts
• EU nominal voltages: 230 V ± 10 % (line-neutral) and 400 V (line-line) [IEC 60038].
• Power-line adapters modulate 2–30 MHz carriers; electronic meters add 20–60 dB loss at these bands [Ofcom, 2021].
• Type-BF electronic meters use shunts, not coils, so attenuation is <15 dB typical [Devolo, 2022].
• 50 m ready-made extension leads cost €25–€40 in EU DIY stores [OBI Price-List, 2024].
• Safety limit in wet rooms: max 50 V AC touch voltage [IEC 61140].
How can I tell if my apartment socket and basement socket share the same phase?
Measure phase-to-phase voltage: 1. Run an extension lead from the apartment’s phase conductor to the basement. 2. Set a CAT III-rated multimeter to 600 V AC. 3. Probe between the two phase pins. ≈0–15 V means identical phase; ≈380–415 V means different [Elektroda, Fazi87, post #11276091]
Is the light-bulb-between-phases trick safe?
No. A regular 230 V bulb sees 400 V across two phases; filaments can explode and throw glass. One installer lost an eye using this method [Elektroda, zbich70, post #11290403] Use a proper meter, not a bulb.
Will my electronic energy meter block a power-line (PLC) network?
Many electronic meters use shunt sensors, giving <15 dB loss up to 30 MHz, so PLC may work. Electromechanical coil meters add >40 dB and usually stop the link [Devolo, 2022].
What if the two sockets are on different phases—can PLC still work?
Some adapters link phases capacitively in the building panel, but throughput drops by ≈70 % and connection can be unstable [Ofcom, 2021]. A certified phase coupler in the switchboard solves this.
How long an extension cord do I need for the voltage test?
A 3-storey drop needs ~20 m; 50 m factory-moulded cords are widely sold, so length is no obstacle [Elektroda, zbich70, post #11277413]
Could the basement outlet be low-voltage instead of 230 V?
Yes. Some blocks feed basements with 24 V for damp-area safety [Elektroda, Novile, post #11280812] Verify with a multimeter before plugging PLC gear.
What equipment rating should my multimeter have for this test?
Choose a 600 V CAT III instrument; it withstands phase-to-phase faults in a 400 V system and meets IEC 61010 safety rules [Fluke Manual, 2023].
I confirmed the same phase, but the link still fails—why?
RCDs, surge filters, or poor wiring can attenuate PLC carriers by >30 dB. Bypass the RCD briefly (qualified electrician) or use a Wi-Fi mesh as fallback [Devolo, 2022].
Is there a quick alternative check without meters or cables?
Yes: plug both PLC adapters in one room first. If they pair, move one to the basement. Link OK → same phase and meter transparent; link lost → phase, meter, or filter blocks path [Elektroda, 15kVmaciej, post #11278799]
What are safer non-PLC options for basement networking?
- Run Cat 6 Ethernet down the stairwell using trunking.
- Deploy a Wi-Fi access point in the basement fed by fibre-optic-USB extender.
Both avoid 400 V risks and deliver >1 Gbps reliably [Cisco Design-Guide, 2023].
- CLOSING
