URGENT! The correct fuse in plugs....

[admin_exported]

Evening, i have taken delivery today of some mains cables for various bits of kit. I did specify the gear that the mains leads would be feeding when i ordered. They have all come with 13 amp fuses. Now only one lead that i am replacing is actually 13amp. The other two are 5 amp. One for the TV and one for the sub.

My question is, when they are plugged into a mains conditioner, will this be ok or do they need to have the correct 5 amp fuse in the plug?

Ta

 

[daveh75]

Yes it's important from a safety point of view.The fuse isn't there to protect the equipment,but the cable itself, from potential overload should a short/fault occur!!!

Just replace the fuses in the new leads with the 5A ones from your equipments original leads.

 

[Anonymous]

Thanks

I only actually have to replace one at this moment in time due to the fact that the one for the tv doesnt fit in the tv properly and hence doesnt work at all!!

Not happy at all.

 

[kena]

Odd I know but RA only sells 13a fuses doesn't do 5 or 10 , I bought Audiophile fuses for correct rating from flea-bay

 

[Anonymous]

If the new mains leads (from a reputable mfr) were supplied with 13A fuses one has to assume that the leads are rated at 13A or above. So no, the 5A should not have to be fitted. However using the 5A fuse is perfectly acceptable. (find which sounds/pictures better)

 

[Anonymous]

Thanks fellas. My old man has also told me 13 would be fine and that the RC would trip if there was any issu anyway........

 

[Anonymous]

kena:

Odd I know but RA only sells 13a fuses doesn't do 5 or 10 , I bought Audiophile fuses for correct rating from flea-bay

As daveh75 says the fuse only protects the cable from the plug to the equipment it is feeding. So RA not supplying 5 or 10amp fuses is fine as long as the leads they offer are rated 13A or more.

Do the audiophile fuses make a noticable difference?

 

[daveh75]

scowl:
If the new mains leads (from a reputable mfr) were supplied with 13A fuses one has to assume that the leads are rated at 13A or above. So no, the 5A should not have to be fitted.That's actually a good point,and something i overlooked

 

[gpi]

A guide that I always remember is if the component or appliance operates at 750 watts or higher (e.g. a kettle), it needs a 13 amp fuse. Anything below 750W needs a 5 or 3 amp fuse. The wattage something runs at will always be printed clearly on the label on the rear or back.

 

[hammill]

gpi:A guide that I always remember is if the component or appliance operates at 750 watts or higher (e.g. a kettle), it needs a 13 amp fuse. Anything below 750W needs a 5 or 3 amp fuse. The wattage something runs at will always be printed clearly on the label on the rear or back.I=P/V. So a 750 watt appliance would need a fuse of 750/230 = 3.26 amps. Rounding up to the nearest commonly available value gives 5 amps.

 

[gpi]

From wikipedia:

3 A fuses are intended mainly for small load (less than 750 W) appliances, such as radios and lights. 13 A fuses are for larger load (less than 3.2 kW) appliances, such as heating and heavy-duty electric motors.

BS 1362 requires that plug fuses with any other current rating be marked in black. 5 A fuses are also commonly used for medium load 1250 W max. appliances such as desktop computers and TV sets. Ratings of 1, 2, 7, and 10 amperes are also produced but rarely used. (1 A, as found in some shaving-socket adapters, is 20 mm long (BS 646), but a BS 1362 version does exist).

Rewirable BS 1363 plugs are always sold fitted with a fuse, usually 13 A. This fuse must be changed if fitting the plug to an appliance or flex which requires a fuse with a smaller rating. Plugs with smaller fuse sizes already fitted are sold but are not as common.

Well there's my theory out the window, doh.

 

[kena]

scowl:kena:

Odd I know but RA only sells 13a fuses doesn't do 5 or 10 , I bought Audiophile fuses for correct rating from flea-bay

As daveh75 says the fuse only protects the cable from the plug to the equipment it is feeding. So RA not supplying 5 or 10amp fuses is fine as long as the leads they offer are rated 13A or more.

Do the audiophile fuses make a noticable difference?

Not that I noticed, but due to the the low cost it's not a big deal and I was using RA fuses anyway..

 

[wireman]

daveh75:Yes it's important from a safety point of view.The fuse isn't there to protect the equipment,but the cable itself, from potential overload should a short/fault occur!!!

That is technically right according to the IEE and BS7671 (the electricians' standards) - the principle purpose of the fuse is there to protect the cable. But the fuse also affords a degree of protection to the equipment, and a lower rated one will disconnect the circuit sooner should a fault occur. Although most electronics have even lower rated fuses internally to protect the item, by using a 13A fuse in the plug of a device drawing probably less than 2 amps means the equipments' internal fuse is most likely to fail first, requiring a trip to the repair shop. So even if your fancy mains cable is capable of feeding a small sub-station, it's worth changing the fuse for a lower rated one more in keeping with the current draw of the item itself - typically 5A for most source components, and using 13A only for larger power amplifiers and AV receivers.

Me? I've bypassed all my fuses and have my equipment hard-wired into dedicated circuits and protected by MCB's (miniture circuit breakers), which operate more quickly than fuses, and are generally acknowledged to sound better than fuses too. If you ask any of the people who actually make these fancy mains cables, that's generally what they've done in their own homes too. The point here is that all fuses (however "audiophile" they may pretend to be) do have a 'sound' and are inferior to alternative methods of protection... I even have a friend who polishes his fuses with Duraglit, and swears they sound better!

 

[Anonymous]

Wireman,

I am suprised that circuit breakers sound better than fuses. CBs are more complex and put an inductance directly in-line. I would have thought this would cause phase-shifty current laggy problems.

Barring the old re-wireable fuse, circuit breakers are still generally regarded as slower acting than fuses.

 

[Anonymous]

Some interesting stuff gents.

I have now swapped all the fuses in all cases to the ones that were in the original leads.

 

[wireman]

scowl:

Wireman,

I am suprised that circuit breakers sound better than fuses. CBs are more complex and put an inductance directly in-line. I would have thought this would cause phase-shifty current laggy problems.

Barring the old re-wireable fuse, circuit breakers are still generally regarded as slower acting than fuses.

If you look at the up-market range of mains conditioners from people like Isotek and Isol8, you'll see they use circuit breakers on their devices in preference to fuses. I think your views about "inductance and phase-shifty current laggy problems" are usually associated with RCD's, not MCB's. An RCD (Residual Current Device) detects an imbalance between L and N by running the current through a coil... any imbalance, and it trips. It serves a different purpose to an MCB, and should be used in addition to, not instead of an MCB on normal domestic circuits - the primary purpose of an RCD being to detect current 'leakage' in ciruits used in potentially damp locations (kitchens, outside plugs, garages etc). In mains circuits dedicated to hi-fi or home cinema, the common view is to avoid using RCD's on that circuit.

If you look at the electricians handbooks (BS7671), you'll see there are tables for maximum specified trip times for all types of devices intended to disconnect a faulty circuit - fuses and MCB's - and the maximum permissible current it's allowed to pass before that device disconnects. In reality, a BS1363 13A plug fuse can pass a maximum of 26amps for a short period before it "blows", and in my experience, an MCB will usually disconnect a circuit much more quickly than a fuse. But what do I know? I'm only a humble electrician who installs dedicated mains circuits for hi-fi buffs!

 

[Anonymous]

I agree with what you say Wireman.

My system is hard wired and circuit breakers are used throughout.

Also the dedicated mains spur is put through a Tacima 6 way block before feeding 2 x BT Mains conditioning units (which have built in mains reservour capacitance and isolation transformer) hence no restiction to high current flow surges.

Result ---- A totally clean power supply with a noise floor that has disapeared.