Phase tester useful?

For power sockets I use a Powerquest 2. Next to that I have no clue if the phase side of my wall sockets are left or right. Does it help to test all phase from my equipment? I have (borrowed) an Oehlbach Phasetester but no clue how I need to put the pins into the sockets …

With Schuko, yes. All Naim gear comes with a phase marker on the original Naim Schuko-IEC cable (the kind of marker depends on the manufacturing year). For non-Naim, there are phase testers like the Oehlbach “Phaser” or the Clear Compontents Phase Detector. (Edit: I see now you borrowed the Oehlbach)

The units should all be plugged in correctly in-phase. Some hifi power strips come with a light indicating which side the phase is. If you don’t use a strip or it has no such light, use a simple pen phase tester

Thanks but when I know which side the phase is, i still do not have a clue how to plug it into the sockets… (by the wayI use different power cables not the original Naim ones)

You plug the power cable into the unit and use the Oehlbach to find the phase pin. Mark this side of the power cable plug with a paint marker or something. Then use the pen phase tester on the wall socket, it will light up in one of the socket holes. Plug the power cable plug into the socket so that the phase-marked pin goes into the socket hole where the pen lighted up. Repeat for each device and socket

Cheers thanks. Then I only need to borrow a pen phase tester and get the job done. I have small stickers for on the pins as marker.

1 Like

With the pen tester inserted into the socket hole, put the index finger onto the metal part in the red cap at its top, then the pen will glow

1 Like

Do you mean phase?
Or do you mean whether live or neutral?
It might be a language thing, but in English in the British Isles phase is something very different in electricity distribution, where most homes have a single phase at 220V, where as offices, workshops and factories can use upto three phases, but obviously are higher voltages like 415 volts.

Neutral is the return or ground, and depending on distribution is at or close to earth potential on a local mains distribution. Live is the ‘hot’ line and is at mains potential.

The UK square pin plugs clearly differentiate between live and neutral.
There are some limited low current devices which can use round pin plugs where netral and live are interchangeable, but by definition these can’t be earthed.

However mains live testing neon screwdrivers are inherently dangerous… if they develop a fault they can be lethal, I really would recommend using a cheap AC volt meter instead… the live line with respect to ground/earth will have the largest voltage.

1 Like

In Germany with Schuko, one of the plug holes is called the “phase” in German, what you would call the live one. the other round hole is neutral. The flat bits top and bottom are ground

Maybe, but a cheap AC volt meter can also be lethal when faulty. Never heard about an issue with the pens/screwdrivers in 55 years of living here

Thanks for the background and warning… i live in Holland we have AC/DC 220V. But i totally am not familiar with current and how it all works so I only understand half of your reply sorry.

How so… other than in act of god scenarios. A voltmeter measures in isolation, a mains tester screwdriver uses YOU to complete the mains circuit to light the neon… and yes if working correctly they are ok, but there is no protection to you should a fault arise.

Issues with main tester screwdrivers… the web is littered with warning and issues…

Anyway personal choice whilst legal… at least others reading can hopefully take an informed risk assessment. Measure in isolation, or measure using your body as the test circuit with a neon screwdriver.


Hi again Simon, I thrashed the “phase” word to death a while back with Peder - remember him ?.
Phase is the word thats commonly used throughout Europe to describe L & N polarity issues with the various EU plugs.
I had difficulty with this in my European training schools, I had to insist on “polarity” for L & N single phase for standards compliance. Fortunately 99% of the equipment was 3 phase.

1 Like

There is live, neutral and earth. Some continental supplies seem to provide only live and neutral.
The hot connection is the live.
The neutral is the return or ground. It is typically earthed at your substation, distribution transformer or sometimes at your home.
The earth is the earth potential at typically your home or sometimes your substation.

Therefore the voltage across the live to earth will be around mains voltage. The voltage across neutral to earth will typically be 0 to a few volts… but occasionally more, but less than the reading for live.


Everyone can decide for themselves. Hundreds of millions of Schuko users have been using them for decades, but yes, use a proper meter if concerned.

By the way, even cheap voltage meters usually have a “phase” mode over here, so your description of measurement is correct but usually not needed. Just put the meter into “phase” mode and it will light up the same way as a screwdriver tester would glow

1 Like

The Oehlbach Phaser is usefull but strangely doesn’t seems to work with Naim gear. On a CD555 PS and on the 300 PS, it indicates that the phase is on the upper pin of the IEC input instead of the bottom pin (Naim’s recommendation). Another guy tested his XPS and had the same inverted result with the Phaser. I tried with the Live on upper position but it sounded worse (more treble, less bass, not a well balanced sound). The Phaser works well with all other non Naim stuff, even a Nordost QB powerstrip has it’s own polarity to work optimally.

Thanks. It only worked well for my power cables (non Naim). Still try to figure out what the phase is in the AQ Powerquest sockets. I seem not to be able to get a pen in properly to check this…

IEC320 orientation is as shown in this drawing.
The “Socket (Female)” is the plug thats on the cable
The Live (L) should light your voltage indicator (phase tester as you call it)
If the Neutral (N) lights the tester, you need to reverse the Schuko plug.

This (Oehlbach, etc.) tester tests the “phase” of the unit, not of the Schuko wall socket! Remember that in UK you don’t have to do this, as the plug can only be inserted one way into the wall socket. I.e., the connection from the IEC holes/pins to the pins on the UK plug is unambiguous.

In Schuko countries, however, the connection from the IEC holes/pins to the pins on the Schuko plug IS ambiguous and you don’t know for sure which pin of the Schuko plug on the cable carries the “phase”. This is what the tester is for. The Naim-supplied cables have a marker so you don’t have to do this, but other cables don’t.

So you plug the IEC end of the cable into the unit and plug the Schuko end of the cable into the tester, which tells you which pin is live. Then orient it correctly when plugging into the wall socket (as indicated on the socket by the glow of a screwdriver tester or whatever safer tool).

Interesting that @Nico says that the Oehlbach does not work with Naim. I have the Clear Components and it does (i.e. has the same result as the marking on the Naim cable)

Yup not generally permitted in industry, I watched a chargehand take one from an apprentice and smash it! “Not in my factory!”


I’m well aware of what the Oehlbach Phaser does, also the differences in EU & world electrical standards, I managed company training & had trade schools in Ireland, Belgium, France & others outside EU around the world.
I posted the IEC320 plug orientation as (IMO) its easier for other readers to understand what the objective is.

1 Like