Advice needed - mains cable to run on outside wall.

[jamesn333]

Hello folks,

I'm looking at adding a new dedicated spur for a Hi-Fi system. Spoken to my electrician and i'll do the cabling and then he'll do the final checks and connection into the Consumer unit. No probs there.

My problem is the cable run - The easiest cable run would be to take it along a 20m run on the outside wall between garage and lounge.

SWA seems to be the best if running outside - i'm concerned about making a neat job and wondered whether its against the regs (or bad practice) to run Twin & Earth instead and run this in conduit to provide mechanical and UV protection. Can this be standard round PVC conduit ?

Your advice would be very welcome.

rgds

James

 

[Chri5]

A spur is run off the existing circuits, by the sound of it you wise to provide a dedicated 'pure' radial just for your Hi-Fi

Please explain why you need this, is it a £15k krell setup

The vast majority of music equipment doesn't require anything other than a couple of sockets off an existing ring circuit and before I go further I would like to question the logic your using.

On a further note, if an electrician is doing the connectivity then I assume they will be doing the circuit design and as such they should be telling you what they want regarding cable size, type, route and protection / containment.

PVC conduit is not suitable for outside use and has zero mechanical protection and will become brittle due to UV, hot, cold and wet weathering.

If the run MUST be done externally SWA or an MICC / pyro cable would prevent the need for steel conduit and earthing for the conduit.

 

[jamesn333]

Appologies - meant a radial.

No need to question my logic and thanks for the answer on the conduit - SWA it is then.

Thanks

James

 

[sm1thson]

The easiest cable run would be to take it along a 20m run on the outside wall between garage and lounge.

when you take into account the cost and hassles of working with swa, is this still the easiest/ best route?

 

[Chri5]

We are here to help.

If offering a cheaper- easier- quicker solution is the wrong thing to do, then I have no need to question your logic or enquire as to why you feel there's a need to provide a separate radial.

That's between you and your money.

Had you offered an explanation (and as you rightly mentioned that wasn't your OP question) someone might have saved you

a cheaper- easier- quicker solution

Have you consider the load of the equipment you intend to run, the number of sockets required, drip loops on th entry / exit points, diagonal drilled break ins and outs, glanding method of SWA (lugs, piranha nuts), SWA box positioning and IP rating.

Then there's the potential need for a clean earth or HI earthing.

Either ask here or better still (due to on site knowledge) ask your electrician.

Thanks for the thanks

 

[jamesn333]

Ok - let's start again then

With a reasonable amount spent on Hi-Fi (not quite 15k on a Krell system but 7k on a Naim one) a dedicated mains supply seems to be a reasonably cheap way of getting the best performance - the system sits on the end of a mains connection with nothing else hanging off it.

What i want to achieve is here

http://www.acoustica.org.uk/t/mains.html

So... if we can avoid any **** taking on my audio spending - what would you guys recommend. The route around the outside of the house seems simplest as i dont see any other way of getting cables across the house without channeling out concrete floor or lifting floorboards.

Cheers

James

PS - and no i wont be doing the dedicated Earth - too many complications and issues with that from a safety point of view.

 

[RF Lighting]

What a crock-of-****.

Running a radial from the CU to your dedicated hifi socket will make NO difference what so ever.

There may be a very slight reduction in impedence of the circuit from the CU to the hifi socket, compared with a socket supplied by the general ring circuit, but when you remember the hundreds of meters of 100 year old LV cable supplying your cutout, and not to mention the rest of the street, which will be riddled with joints all the way back to the substation, where it connects to a big old transformer, and then to miles and miles of cable back to another transformer, which is subjected to allsorts of abuse from the environment, including lightening strikes etc., and then eventually to the power station, reducing the overall impedence of the circuit by maybe 0.03 of an ohm really will make no difference.

Have you thought about buying a better IEC lead?
There is one here for just £1805.00

 

[RF Lighting]

Fit a spur not a ring. We've built both and the spur simply sounds better, regardless of what Russ Andrew says. In fact we installed a 30A dedicated ring, then cut it into two spurs after listening to it....

Where are BAS's ROFL emoticons when you need them?

 

[FarmerJon79]

This reminds me of an article in New Scientist when the journalist had been to a HiFi show. Everyone was talking about how amazing a set of £20K speakers were, which a company had just brought out. The journo noticed the speaker flex had a familiar colour to it, and asked the man on the stand. "Oh yes,", he replied, "when we got here we realised that we'd forgotten our cable, so we popped across to B&Q and bought a couple of B&D lawnmower cables, they're 2.5mm2 copper, and work just fine".

 

[jamesn333]

Oh there's a lot of bullshit in it but getting all the other crap that sits on the ring is no bad thing and anyway its my time and money.

I'm just after some advice

James

 

[Chri5]

As mentioned it won't make any difference.

I'd suggest you just work to a local socket or a spur off the existing circuit in the room.

Then consider either a trickle UPS (PC type item sub £100) which can be set to give you a constant in use voltage or a mains filter.

Fortunately my Musical Fidelity pre and power amps came with a dedicated PSU.


The SWA cost, the time running it and the sparks doing the cert will be no less than £250 odd, so consider your options and I promise I won't say "I told you we could help reduce the cost"

You might want to consider that £7k isn't that much, in terms of work on AV and home automation, ambient lighting, room to room sound, multi source, multi room av stuff and there's plenty of folk (myself included) that would see no reason to take the wee about the cost.

if you have the money why not spend it. I have a client with 5 x £100k cars in his garages

Rgds

PS this make a sensible read http://www.soundonsound.com/sos/Jul03/articles/mainsproblems.asp?print=yes

 

[breezer]

I uppose next the OP will be saying he has "monster oxygen free cable" for the speakers.

I agree with RF its all a waste of time and money, it nly sounds better becuse you want it to, after all you just spent a lot of money on it (the cablenot the HI FI)

I honestly believe its a load of woolabrawonga made up by HI FI sales companies just to get a few more quid out of you

I run my 200w speakers on a bit of alarm cable. they sond fine, ask the neigbours

 

[jamesn333]

Well my original question was answered so thanks again.

Right i'm off to oxygenate my cables and then off down the pub

Cheers all.

James

 

[RF Lighting]

Will you send me some of your money please?

Have you thought about installing superior ring main cable?

When you’ve upgraded your mains cables and extensions all the way back to your wall socket, you’ll know how big the improvements in performance can be. Now do it to the cable that runs from your consumer unit (fuse box) to the wall socket and prepare to be amazed!

Russ Andrews Superior Ring Main cable is our best cable for the job, using the highest purity copper and insulation. Your system will sound sweeter and more natural, rhythmic and musical.

Sold in 1m lengths with a minimum order length of 5m. Enter length required in quantity field, eg. Qty 20 is 20m.

Please note: The installation of any mains circuit must be carried out by a competent electrician, holding Part P and Edition 16 of IEEE regulations.

SPECIFICATIONS
• Number of conductors - 16 (eight Live & eight Neutral, colour coded brown & blue)
Total live or neutral conductor diameter – 4mm

• Conductor material - Hyper-Pure OFC Copper

• Cable rating - 30A (7.65A per mm² @ 20ºC)

• Central Earth wire - 1.5mm²

• Total cable diameter - 10mm

• Insulation - Teflon dielectric

The cable is supplied in single insulated form. For installation purposes the cable must be double insulated, which can be provided at additional cost.

ROHS Compliant

We recommend the cable is installed in conjunction with a 16A circuit breaker.

 

[Wontdothatagain]

Resistivity of 2m of pure copper cable 2.5mm csa (no plug or socket) =0.01376ohms

Resistivity of 2m of pure gold cable 2.5mm csa (no plug or socket)= 0.01952ohms

Resistivity of 2m of pure silver cable 2.5mm csa (no plug or socket)= 0.01272

First thing tommorow i am going back to the hi-fi shop and shoving those gold coated terminal leads where the sun does not shine.