RCD Tripping from Power Saw

Andrewbullie · Jan 22, 2013

Hi All,

I have a 2400w power saw on 230v which is tripping after about 0.3 seconds. It is running of a 16A RCD with no other devices on the circuit. Could this be caused by a high current demand at the start up or is it more likely to be something else?

My calculations reckon that it should draw 10.5A, but if it was a short, would it allow the saw to start enough to spin the blade like it is?

PS, I'm not an electrician as you may have guessed but have a limited knowledge.

Cheers

Andy

Silly Sausage · Jan 23, 2013

Can I suggest that you post as many pictures as you can. of the DB, breakers/RCDs/equipment/tags on the gear etc etc........

Andrewbullie · Jan 23, 2013

Will do, do I have to upload the picks to Flickr first and then input URL?

Darkwood · Jan 23, 2013

It sounds like it tripping on inrush then, a C type may cure this ( no promises) but is only an option if the ELI would comply to regs otherwise plug into a Ring main elsewhere and i suspect you wont have any problems as this other Ring should have a 32a mcb covering it which is the problem with the shed as you cant upgrade the mcb to larger size due to supply cable size.

Darkwood · Jan 23, 2013

Plug into a standard ring main i believe this will cure your problems ...the shed set-up dosn't sound like you can adapt it to work and yes the motor inrush on the 16b mcb sounds like your culprit.

Andrewbullie · Jan 23, 2013

So if I don't find a problem at the workplace tomorrow then I could upgrade to 32a and place cable with 6mm?

Darkwood · Jan 23, 2013

Andrewbullie said:
So if I don't find a problem at the workplace tomorrow then I could upgrade to 32a and place cable with 6mm?

You mentioned you supply to shed is 2.5 if im right this means you cant upgrade this mcb without upgrading the shed supply and i wont make suggestions because it really needs to be looked into on site .. a little bit of missed info' could end up with you getting incorrect advice.
Its clear (no disrespect meant) that your not an Electrician as you struggle to identify the protection devices so i advice you get someone to have a look what it would entail to increase the mcb rating to the circuit as it may require a new shed supply etc etc..

Geordie Spark · Jan 23, 2013

Tony said:
Is this in the same building you were going to have demolished?

No .......... you're getting confused with the 3,000+ Clubhouse. :jester:

Andrewbullie · Jan 23, 2013

Well, I took the saw in to work today and tried it...... Ran sweet as a nut!!

So, it looks like I need to upgrade my supply. I had a word with one of the electrical guys at the calibration site this afternoon and he reckons change from B16 to a C20. I since checked the supply and discovered that it is actually 2.5 SWA cable on a run of approx 8 meters not twin & earth like originally thought.

plugsandsparks · Jan 23, 2013

How is the shed/garage fed from the house? Does it have its own breaker or is it fed from the sockets via a spur or something. You may end up passing the problem further up the chain as it were. C20 is worth a try, there is the little issue of having a good enough earth to make sure it trips when required if there is a fault. Could one of you electricians at work do a drive by and measure the Zs from a socket in the shed, will only take a minute, then at least you and your shed are safe.