13A fuses - is there much difference?

[flintandsteel]

Might sound a bit odd but is there much difference between brands?
Every time I start my planer it pops a fuse. New fuse and it starts and runs just fine - on / off all day long.
All I'm wondering is there any difference between manufacturers as all 13A's should be doing the same job?
Guess it's the load at start up does it. Or is it sounding more of a machine rather than a fuse issue?

 

[deema]

The legally compliant ones are all the same. However, they pop at around 20+Amps usually, with a lot of variation. Age reduces the pop current level as does frequency of over current. So, a fuse could go at 15A first time in use and another at 25A.
I’m guessing you’re running something with a motor larger than 1.2KW motor in it on a domestic plug. Thats not going to work and is going to continually blow fuses as it should.

 

[ChaiLatte]

It is possible to buy legally co pilot 13A fuses called 'slow blow'. They are designed exactly for situations like this. Just one example (wood chipper manufacturer):

https://forest-master.com/time-delay-fuses-x2/

You would find them at a proper electrical retailer or RS.

Amazon/China ones are likely to arrive either pre-blown or with a 4" nail offcut inside them, neither of which is desirable.

 

[Jester129]

Cynicism rules, yeah!

 

[Spectric]

The problem is that your machine really needs to be on a 16 amp supply, it should not be a case of " oh just replace the fuse again" as the fuse is doing it's job and you will be stressing any up line protective devices. Many of us have had similiar issues and my Record PT107 was just the same, startup current was way to high for the 13 amp fuse and so I fitted a 16 amp circuit with a new 20 amp type B RCBO in the board and no more problems.

A lot of components such as protective devices and such are now made in asian countries as well as places like Poland and Hungary but may still retain some historical company name so don't always believe the badge.

 

[AndyMc]

and so I fitted a 16 amp circuit with a new 20 amp type B RCBO in the board and no more problems.

I do hope you mean '...I had a qualified electrician install a new 16a circuit, complete all the safety checks and then notified the local authorities...'

 

[Spectric]

I am a qualified electrician who has worked mostly on three phase industrial, working in domestic you find to much dangerous bodging because people just do not realise that just because it works does not mean it is safe.

 

[Mel769]

I would advise to follow the manufacturer's instructions on fuse size, if the equipment is made with a lead and 13a plug then use just that. Only use fuses from a reputable brand; bussman springs to mind. Not too long ago I read a piece about knock off plug fuses that are poorly made flooding the market; the sort of brands you might find in the pound shop ect; and not really type tested to British /EU standards so probably be mindful of that. If its regularly blowing fuses then likely be faulty equipment imo. I'm a spark aswell and would deduce from the symptoms that maybe the equipment has an intermittent earth fault.

 

[Mel769]

Almost forgot to mention; is the equipment dated ? If it was made some time ago to run on 240v then that might be the issue. Harminization of voltage across Europe nowdays to 230v +- wherever (sometimes it is still around 240v though) means if the voltage is lower (say 220v) then current is higher. An example would be the old immersion tanks that often used a 3 prong plug & socket or 13a spur. Nowdays with the changes in voltage to 230v these immersion heaters with 13a plugs/spurs can often overheat due to the additional current draw; so its recommended to put immersion on a 16amp circuit and use a 20a switch for local isolation.

 

[Sideways]

Nowdays with the changes in voltage to 230v these immersion heaters with 13a plugs/spurs can often overheat due to the additional current draw

The UK hasn't changed to 230V
Our standard has been written as 230V +10% -6% since about 2003 as part of european harmonisation (and new appliances in Europe are required to work with supplies of 230v +/-10%) but the nominal mains voltage in most places in the UK is still 240v.
240V falls within the range allowed by the "new" 2003 standard.

@flintandsteel 's problem is almost certainly down to overstressing fuses due to the excess current during motor startup. It's a commonly seen seen problem exactly as @deema and @Spectric describe.

It is an issue though that more EV charging, more heat pumps and more solar PV all make it harder to keep the mains voltage within it's allowed limits, both high and low. In my neighbourhood, the mains is often above the 253V maximum. I'm sure there are others where a bunch of EV car chargers turning on in the middle of the night makes the voltage sag below minimum.

 

[Scruples]

I do hope you mean '...I had a qualified electrician install a new 16a circuit, complete all the safety checks and then notified the local authorities...'

I did all my wiring in my workshop. It was for me, and the local authorities weren't informed. And yes, I have a BS4343 socket for my TS which runs off the ring with a 16A breaker. It's unlikely I'd used two or more machines simultaneously.

 

[ChaiLatte]

I am a qualified electrician who has worked mostly on three phase industrial

With regard to the OP's problem, is there any utility in suggesting or discussing a soft starter module for his machine?

They are available at RS for £2-300. The cost might be less than or equivalent to having a 20A circuit installed (and since the device does not form part of the fixed wiring, going after the plug on the machine, it might not need all the paperwork).

 

[MorrisWoodman12]

An interesting aside to this issue has happened to me. I have had an old Elektra Bekum planer thicknesser for several years which is connected with a 13A plug. Before I moved house it would break the 13A fuse on start up. Not the one in the plug but the inline one in the isolation switch as the 25meter SWA cable workshop feed exited the house. It blew about every 6 to 8 weeks. I'm a hobby woodworker so it didn't get used that much. Now I've moved house my workshop has been wired (professionally) back to the house consumer unit, about 15m of SWA, with a secondary CU in the workshop. The PT is connected as before into the workshop 13A ring and it has yet to trip anything.
Hope you get a suitable answer to your question.
Martin

 

[Spectric]

a soft starter module for his machine

Very common with three phase machinery because a three phase motor is self starting but I do not think it would work with a capacitor start single phase motor. The larger soft starting units for three phase also only work on startup and once up to running speed will bring in a bypass contactor so now no current flows through the unit. I must say I have never really thought about doing this with a single phase motor, but looking at the different motor types might help.

Fitted with centrifugal switch where on startup you have two windings to give the 90° shift and then the centrifugal switch opens to disconnect the startup winding, this could be ok with a softstarter as all it will see at power on are two inductive loads and no capacitors. Another motor that could work ok is the shaded pole types, again no capacitors.

The single or two capacitor start motors are I think a no go as they use capacitors but maybe someone has used them and will give further details.

 

[Mel769]

Thing is if it was working alright before but now its not; then somethings amiss!

 

[TimV]

Picking up on Spectric's point above, you can get soft starters for single phase motors that work fine with the start winding/capacitor/centrifugal switch. I have used a DOLD 9017 (because it switches itself out of the circuit completely after the start). others are available. (Don't be put off by "can't be used for capacitative load" in the data sheet - I checked with the manufacturer and that's a different thing.)
The old-fashioned way is to put an incandescent bulb in series, but you need to experiment to get the right wattage, and it's likely to be more than 100W, so a halogen floodlight bulb, and they're kinda hard to get now

 

[mind_the_goat]

Almost forgot to mention; is the equipment dated ? If it was made some time ago to run on 240v then that might be the issue. Harminization of voltage across Europe nowdays to 230v +- wherever (sometimes it is still around 240v though) means if the voltage is lower (say 220v) then current is higher. An example would be the old immersion tanks that often used a 3 prong plug & socket or 13a spur. Nowdays with the changes in voltage to 230v these immersion heaters with 13a plugs/spurs can often overheat due to the additional current draw; so its recommended to put immersion on a 16amp circuit and use a 20a switch for local isolation.

With a resistive load such as a heater, lower voltage means lower current with corresponding lower heat output. 110V equipment runs at higher currents than 240V because it is designed that way to get the same power output
The relationship between voltage and current with inductive loads such as motors is a little more complex.

 

[sploo]

Amazon/China ones are likely to arrive either pre-blown or with a 4" nail offcut inside them, neither of which is desirable.

I stick it to "the man" by just installing my own offcuts of 4" nails in all my plugs, instead of 13A fuses.



(NB I don't do that... though I may once have replaced the fuse in a knackered PC power supply with an M5 bolt just to find which component really failed... outside of course)

 

[MorrisWoodman12]

The relationship between voltage and current with inductive loads such as motors is a little more complex.

But the relationship is still basically the same. That is good old Mr. Ohms Law still applies though with pure resistance replaced with inductive (or capacitive) impedance -- I = V / Xl where I is current, V is voltage and Xl is inductive impedance = 2 × pi x f (frequency) x L (inductance). This is ignoring all phase shifts. Of course with motors there will be a start up surge.
Things can be confusing if your device uses a switch-mode power supply (SMPS). Then you have to remember that (for a constant load) the SMPS transfers a constant POWER load onto its supply irrespective of its input voltage. That is if its input voltage drops then it draws more current. This is NOT Ohms law.
Martin