Hi there,
I have ungrounded wall sockets (receptacles) where my hifi equipmemt is connected.
Should I try to change this to a grounded wall socket?
Except the obvious safety improvement are there other gains to be had?
Would it improve sound quality?
Thanks
Alex
Atc scm 11/Nait xs2/advanced acoustics wtx pro streamer.
What country are you in?
I live in sweden.
In Europe this is called earth (not ground) although in the USA influenced world it is called ground.
Naim is designed for & requires a safety earth. However it works OK on just L & N, its just not perect & potentally is not safe if some kind of earth/ground fault occurs.
All units with a 3 pin IEC input have the E (earth) connected to the unit case body. Some, but not all, also have a -ve signal connection to earth.
If you do change the power sockets to include an earth, them you must ensure its done correctly as per your national regulations. In UK this must be done by or at least tested & certified by a qualified electrician.
Yes it’s the same in Sweden and you must not mix earthed and non earthed in the same room. Earthed sockets in all rooms was not introduced until 1994 here so a big bunch of people do not have it. If we focus on the sound quality I’m not sure how it is affected. I have read it’s more common with ground level issues with earthed equipment and some also claim non earthed sound more airy and dynamic than earthed sockets. On PS Audio power cords for example you can pull out the ground pin on one end to prevent ground issues.
PS Audio are a USA company, it might be legal in US to remove the earth - oops sorry ‘ground’ - but not in UK
And if you set up your signal grounding correctly, you will not have ‘ground issues’
From what I can see in Sweden there is either type C socket-outlets, for 2-pin class II (double insulated) equipment and type F socket-outlets, for classI (earthed) equipment. As most Naim equipment is class I (earthed) you should only use the type F outlets to ensure safe operation. However, the potential hazard of using the wrong socket will be mitigated if the mains supply is protected by an RCD, which I suspect will be normal.
Thanks for all the replies.
@XMB you seem to be contradicting yourself. Are you saying I should use earthed type F? You said it is for class 1 and Naim is mostly class 1 but also that i should use type C.
I currently have type C in the living room. This is odd because most other rooms have type F. The house is a townhouse from 1987. Not particularly well built.
Edited my post to correct the typo.
My living room only has unearthed type C and i think it’s generally fine. In my country (Netherlands) type F only became standard around 2000, houses built before that usually only have it in ‘wet’ rooms.
I do have an earth leak breaker in my main circuit box so i trust that to keep everything safe. I’ve had the circuit break once or twice in the past when i had a faulty microwave oven, and it hasn’t affected my living room equipment.
Although an 30 mA RCD will provide electric shock protection in case of a fault it does not provide protection if the current is below this level.
A class II appliance can have up to 0.25 mA leakage current (new products must be below 0.1 mA). This is current that can flow from touching a conductive part (e.g. metal case) and an earth (e.g. water pipe, radiator, etc.). A class I (earthed) product can have a earth leakage current of up to 3.5 mA (typically 1 mA or less). If you plug a class I appliance into an unearthed socket-outlet then when you touch the metal case, which is now unearthed, and a real earth (e.g. water pipe, radiator, etc.), then the leakage current will flow (say 1 mA) through you. If you connected together 10 class I appliances, for example with audio interconnect cables, then the sum of all leakage currents would flow through you when touching ANY of the appliances and a real earth. This would mean 10 mA of current flowing, which could cause muscle contractions and prevent you from actually being able to let go! If the current path is across your diaphragm it may be enough to stop you breathing!
So, the message is be careful when plugging earthed appliances into non earthed outlets, especially if connecting multiple items together with connecting cables, or a mains extension that connects the earths together.
Sweden is very similar to Japan in this respect. Most Japanese hifi has no use for a mains earth so it isn’t an issue. However, for my Naim office system and equipment for work that must be earthed I resolve the issue like this:
Run an single earth lead from a 50m drum off the nearest earth screw post. That is probably near the plug socket for your washing machine or fridge. If those use regular 3 prong earthed sockets, you can buy plugs at the hardware store that simply provide an earth screw. tack this to the skirting and at the point where earth is required use a mains block with an earth in screw. In this way, the mains block gets regular L&R fron the wall and earth via the long earth run. Ideally space connectors should be crimped to the ends of the cable to avoid bare wire connections.
I reccomend mains blocks that are designed for this so that it is an intended use case and not some dodgy DIY electrical hack.
Here’s an example of such a mains block connected to external earth.
That is totally not legal in Sweden. Either you use non earthed sockets in your room or earthed. Never mix nor run earth wire from other places to a non earthed room.
I have a similar situation in France, no earth pin in the livingroom sockets but they’re there in the kitchen and bathroom. If I remove the socket I want to use for the system there is an earth wire, it even has a loop which gives enough slack to cut it and connect the cut ends to the earth terminal of a suitable socket. Presumably the earth is en route to the outside socket on the balcony but why the loop in just the right place if you’re not meant to connect it?
One thing that was a little worrying was the dirty great wood screw protruding into the back of the socket receptacle from the next flat, it was only by luck it hadn’t damaged the wires. I’ve cut the blighter back and fitted an insulating cap over the stub.
I would ensure your mains follows local specs. Earthing means the earth is connected to earth potential and is physically connected to earth… ground means it is not connected to earth, but is zero potential. Grounding won’t provide a safety function necessarily, where as earthing will. They are often used interchangeably, but technically they are different and carry different symbols.
I would ensure your sockets are earthed.
The consideration then is whether they earthed locally using TT, or a remote earthing at your substation, some sort of PME. Your electrician can advise.
I prefer TT, as the earth carries lower electrical noise.
I believe local earthing is not legal in my country, but i’m not fully up to speed with the regulations…
Where are you from then?
Netherlands
Ok… I do think Naim sounds best when earthed, as it is also used as a signal ground reference via the NAC powersupply… but that is subjective taste. But Naim uses a three pronged mains connector,so is expecting earth.
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