Dedicated Spur advice please

I have realised that in the past I had a problem using both plugs on a double socket to power up components in my hifi...it seemed to cause some kind of  “circular” currents which caused audible noise in the system. It was resolved by using a plugboard into one of the sockets.

If I get a single socket  (for the hifi) and a double socket off another spur (for other stuff eg to power the BT Wi-fi kit) would this make sense?

I would need a powerblock - any suggestions?

thank you

Had a spark round tonight for an estimate; he tells me that unswitched sockets are no longer allowed as there must be a local means of isolation. Googling around it seems to be a grey area in terms of interpreting the regs and their meaning. Anyone had any issue with this?

 

ChrisR_EPL posted:

Had a spark round tonight for an estimate; he tells me that unswitched sockets are no longer allowed as there must be a local means of isolation. Googling around it seems to be a grey area in terms of interpreting the regs and their meaning. Anyone had any issue with this?

 

That sounds like nonsense. Pulling the plug is isolation but turning off the switch on most sockets isn’t as they are single pole and only disconnect the live conductor. Isolation is disconnecting both live and neutral. As mentioned above, you need to find another electrician.

Mr Happy posted:
ChrisR_EPL posted:

Had a spark round tonight for an estimate; he tells me that unswitched sockets are no longer allowed as there must be a local means of isolation. Googling around it seems to be a grey area in terms of interpreting the regs and their meaning. Anyone had any issue with this?

 

That sounds like nonsense. Pulling the plug is isolation but turning off the switch on most sockets isn’t as they are single pole and only disconnect the live conductor. Isolation is disconnecting both live and neutral. As mentioned above, you need to find another electrician.

If I was going to use switched sockets, I would only buy DP ones, and I would guess that single pole switches are only bought by cheapskates looking to save a few pence on each one. For HiFi use, though, my electrician was happy to fit unswitched ones. 

ChrisR_EPL posted:

£500+. Stuff that.

Bear in mind that a good electrician will charge £250 a day, or more, plus materials. I paid £200 about 15 years ago. Also bear in mind that a single Powerline costs over £500. An electrician will charge more if they don’t really want or need the work. The important thing is to get someone good. 

ChrisR_EPL posted:

Had a spark round tonight for an estimate; he tells me that unswitched sockets are no longer allowed as there must be a local means of isolation. Googling around it seems to be a grey area in terms of interpreting the regs and their meaning. Anyone had any issue with this? 

There's nothing in BS1363 (plugs & sockets) or BS7671 (IEE Wiring Regulations) prevents unswitched sockets being used.   It's a matter of personal choice or common sense w.r.t. its location & application.

ChrisR_EPL posted:

Had a spark round tonight for an estimate; he tells me that unswitched sockets are no longer allowed as there must be a local means of isolation. Googling around it seems to be a grey area in terms of interpreting the regs and their meaning. Anyone had any issue with this?

My electrician's concern was not the unswitched sockets but that the isolation point for the new radial needed to be clearly indicated - i.e. if the lounge sockets were isolated via the existing house CU, the Hi-Fi sockets would still be live and this could be a hazard. Appropriate labelling was used to indicated that the new sockets needed to be isolated from the new CU. See pics on my profile page for details. 

james n posted:
ChrisR_EPL posted:

Had a spark round tonight for an estimate; he tells me that unswitched sockets are no longer allowed as there must be a local means of isolation. Googling around it seems to be a grey area in terms of interpreting the regs and their meaning. Anyone had any issue with this?

My electrician's concern was not the unswitched sockets but that the isolation point for the new radial needed to be clearly indicated - i.e. if the lounge sockets were isolated via the existing house CU, the Hi-Fi sockets would still be live and this could be a hazard. Appropriate labelling was used to indicated that the new sockets needed to be isolated from the new CU. See pics on my profile page for details. 

 

I can understand the logic with labelling, although would think in the sanctuary of one's own household the audiophile would be well aware of the electrical arrangement and implications [or should be].

A horrible scenario is when the occupant audiophile nutcase moves away after selling the house with a dedicated audio main remaining in place, and this may or may not having been explained or fully understood by the new purchaser, who may or may not be an audiophile. Then one day the new occupier of the house uses the Hi-Fi socket to plug in the electric lawn mover, and a little while later while mowing the lawn runs over the cable  : P ....well you can see where this is going. I expect 99% of these dedicated audio supplies are disbanded / completely removed when the house is put on the market, but what about the 1% that aren't?

I can see why some electricians get jittery about fitting them : /

Debs

Being German I may have misunderstood the last comments. If that's the case pls. excuse me!

Having an unswitched spur does not mean (I hope!!!) the spur is NOT equipped with a security device that switches the spur off in case of a shortcurt (I suspect such a device is called MCB in the UK, we Germans call it "Sicherung" or "Sicherungsautomat").

I was told that an MCB deteriorates the sound and a passive security device should be used instead. It is called "Neozed" and simply melts when there is too much current and disconnects the spur before the house burns down.

Looking into how an MCB works it becomes clear why it affects the sound: it adds an inductive load to the spur with all its nice side effects (AC resistance, phase shift etc.) where a passive Neozed is just a piece of metal that has (almost) no capacitance or inductance.

Looking forward to your comments!

Paiste2oo2 posted:

Being German I may have misunderstood the last comments. If that's the case pls. excuse me!

Having an unswitched spur does not mean (I hope!!!) the spur is NOT equipped with a security device that switches the spur off in case of a shortcurt (I suspect such a device is called MCB in the UK, we Germans call it "Sicherung" or "Sicherungsautomat").

I was told that an MCB deteriorates the sound and a passive security device should be used instead. It is called "Neozed" and simply melts when there is too much current and disconnects the spur before the house burns down.

Looking into how an MCB works it becomes clear why it affects the sound: it adds an inductive load to the spur with all its nice side effects (AC resistance, phase shift etc.) where a passive Neozed is just a piece of metal that has (almost) no capacitance or inductance.

Looking forward to your comments!

The UK regulations require an MCB, or in many situations, an RCD, which is thought be some to be worse still for sound quality. They certainly do not permit the use if an ordinary fuse (i.e. a bit of wire that melts!). Maybe the regulations in Germany are different. 

The meaning of ‘unswitched’ in this conversation is just that there is no switch on the socket. 

Thanks for the clarification, Chrissu! AFAIK switches on Sockets are not allowed in Germany (although I've seen some ;-).

A Neozed is not just a wire that melts. It's a precisely defined circuit breaker and comes in different current ratings. They were in widespread use before MCBs become available and look like this:

Mersen 01701.020000 Neozed-Sicherung Sicherungsgröße = D02 20 A 400 V

Paiste2oo2 posted:

Thanks for the clarification, Chrissu! AFAIK switches on Sockets are not allowed in Germany (although I've seen some ;-).

A Neozed is not just a wire that melts. It's a precisely defined circuit breaker and comes in different current ratings. They were in widespread use before MCBs become available and look like this:

Mersen 01701.020000 Neozed-Sicherung Sicherungsgröße = D02 20 A 400 V

Switched sockets are nearly always used in the UK, despite being uncommon in other countries. 

I'm not familiar with Neozeds, so I don't see how they are different from any other fuse? I can't imagine that a UK electrician would be prepared to instal these as an alternative to MCBs, RCDs or RCBOs as seen in domestic consumer units.

Mr Happy posted:

Either fuses or mcbs are perfectly safe and comply with BS7671 electrical regs.

So if I wanted to use a good old fashioned fuse box instead of a modern consumer unit with MCBs, possibly also RCD protected, for a dedicated circuit for the hifi, it would conform to the UK regs?! In the context of this discussion, that appears to be what you’re saying, which sounds unlikely to me. 

Rewirable fuse boxes are not illegal as such,  but any audio-nut who thinks it can be done might find that buying a new fused consumer unit to replace a CB type might prove a bit of a challenge - you can't buy them anymore.   Re legality;  you may be required to replace a rewirable fuse box if other work is undertaken to ensure that the whole system is brought into line with current regulations.

Mike-B posted:

Looking around www - it looks like BS7671 17th edition effective from 1 July 2008 has the change / addition that 30mA RCDs (residual earth leakage current) are required for socket outlets.    (This is for new installs & additions) 

Mike, you've gotta get out more.

ChrisSU posted:
Mr Happy posted:

Either fuses or mcbs are perfectly safe and comply with BS7671 electrical regs.

So if I wanted to use a good old fashioned fuse box instead of a modern consumer unit with MCBs, possibly also RCD protected, for a dedicated circuit for the hifi, it would conform to the UK regs?! In the context of this discussion, that appears to be what you’re saying, which sounds unlikely to me. 

As mentioned above an rcd is now required in most cases but yes you can use fuses of bs 1361 type. The old rewirable bs 3036 type are no longer available but that is not what I was suggesting anyway, and if they are installed in an existing circuit then the circuit has different rating characteristics to account for the fuse type.

nigelb posted:
Mike-B posted:

Looking around www - it looks like BS7671 17th edition effective from 1 July 2008 has the change / addition that 30mA RCDs (residual earth leakage current) are required for socket outlets.    (This is for new installs & additions) 

Mike, you've gotta get out more.

Funny you should say that Nigel, just wot Mrs Mike sez.

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