HEEELLPP!! Bandsaw tripping breaker

[craigs]

Well! Third post in this thread recommended fitting a C breaker. 4 pages of intense electrical theory on, we find the solution was the 5 minute job of fitting a C. Glad you machine is now working as hoped for.

Hahaha I know. Thanks for all the help

 

[toolsntat]

Hahaha I know. Thanks for all the help

In my basic understanding of "fuses ie bigger ones can mask minor faults" was EVERYTHING checked out by the electrician ?
Cheers Andy

 

[guineafowl21]

Well! Third post in this thread recommended fitting a C breaker. 4 pages of intense electrical theory on, we find the solution was the 5 minute job of fitting a C. Glad you machine is now working as hoped for.

Most forum threads are answered in the first few replies, but I find the ensuing debates interesting at times. In this case, the ‘answer’ was a suggestion that turned out to be right, but it could easily have been an earth fault. That’s the trouble with many RCBOs - you lose the RCD/MCB diagnostic step.

 

[guineafowl21]

In my basic understanding of "fuses ie bigger ones can mask minor faults" was EVERYTHING checked out by the electrician ?
Cheers Andy

Good point. You shouldn’t really bang in a slower breaker without checking for faults, and also ensuring the circuit’s loop impedance is low enough. If not, the breaker won’t reliably trip and the result might be fire or shock.

 

[sometimewoodworker]

If I had only a 'this or that' choice I'd go 'D' curve which allows around 12-13 times run current on start as opposed to 6-7 times run current on a "C".

it looks as if your numbers are a bit off
Type B devices are designed to trip at fault currents of 3-5 times rated current.
Type C devices are designed to trip at 5-10 times In (50-100A for a 10A device).
Type D devices are designed to trip at 10-20 times In (100-200A for a 10A device).

While you may be able to swap a type B for a type C you may not be permitted to put in a type D. The calculation for which types can be used are in the regulations. It is very unlikely that a domestic machine will need that kind of startup current.

 

[Jackbequick]

UPDATE:

16 Amp type C fixed the problem and now we are all good......now i just need a decent extractor for it

As you earlier asked about 'combo'....
Glossary :Combo..also known as RCDO is a combination overload breaker with integral RCD (Residual Current Device commonly known as a 'safety-switch'). The switched plug sockets on the circuit, or any circuit, are known as GPO's (general purpose outlets...commonly of course known as 'power points' ). Unswitched outlets are not GPO's.

{Bear in mind that during start-up the saw will well overload the copper in an outlet supplying it. The outlet may eventually get heat damage (cracks, cracked switch, intermittent operation)}

It's worked out as I thought...however I have come back only to do 'heads-up' over the 'unknown' aspect remaining after your advice on 'its working'. If your electrician has read my replies he'll realise I know what I am talking about and not be reactive. After this 'I'm out of here'

I am replying to recommend that your installation be tidied up properly and not just 'it now works.' By the way, if you find it 'dropping out' again 'down the track' the likelihood is that the "C" curve breaker was on the edge of its capability and a "D" might be needed.

Did you install a "C" curve breaker with a 30mA RCD and leave the saw as 'plug-in'? ...or is the saw circuit now separated using a "C" curve breaker without an RCD? or with a 100mA RCD...?

If the GPO's are still on that saw circuit...or the saw is plugged in to an outlet which could be used for other purposes whether you reject that notion or not...30mA protection must be protecting it.

If no RCD of 30mA now exists on that saw-circuit I suggest as previously you can replace any existing GPO's on it using outlets with built-in RCD's ....or....

The alternative, possibly cheaper, is to separate the saw onto its own circuit (with the "C" curve breaker) and connect the saw permanently...Consider this as an industrial environment in which flexible leads can be readily damaged thus connection via a junction box and an industrial type switch using protective conduit if needed to enclose wiring...That way the saw circuit without the RCD protection cannot be used for general purposes.

Having seen injuries:
Band-saw momentum doesn't let it stop immediately on 'disconnect'....for example emergency use of a mushroom headed emergency switch. Only electric or mechanical braking can cause virtually immediate stop of rotation but that's not good enough. Be always alert when using a band-saw and don't use your fingers in line with the saw blade to push work closer to that saw.

 

[porker]

I think some of your terminology is not generally used in the UK and I see there are Australian terms.

As I understand it the OP has a seperate circuit with one 16A outlet purely for his saw. There are no other appliances on this circuit. The remedy appears to have simply replace the 16A Type B RCBO with a 16A Type C RCBO so the overcurrent characteristics now cope with the inrush of the saw. The RCBO will have a 30mA residual current device built into it

Glad you got it sorted

 

[craigs]

I think some of your terminology is not generally used in the UK and I see there are Australian terms.

As I understand it the OP has a seperate circuit with one 16A outlet purely for his saw. There are no other appliances on this circuit. The remedy appears to have simply replace the 16A Type B RCBO with a 16A Type C RCBO so the overcurrent characteristics now cope with the inrush of the saw. The RCBO will have a 30mA residual current device built into it

Glad you got it sorted

^^^^ what he said

its a dedicated circuit as said previously.

 

[Spectric]

Glad to see the problem solved and you had things checked before just changing the protective device.

 

[TheTiddles]

^^^^ what he said

its a dedicated circuit as said previously.

It’s the same guy that’s never seen a 13A socket, so take his advice with that in mind. He may well be dead on for where he lives

Aidan

 

[craigs]

It’s the same guy that’s never seen a 13A socket, so take his advice with that in mind. He may well be dead on for where he lives

Aidan

they got a lot of bloody sneks n spiders though!

Either way it all worked out and everything tested fine. I do wonder though, what kind of electrics others have on domestic supplies. I imagine at some point im going to need to upgrade mine. i couldn't believe one of the small(er) cyclones wants a 20A MCB! Isnt all this stuff frowned upon by the bureaucrats with clipboards in domestic environments?

 

[Myfordman]

The reason higher rated MCBs are called for is the inrush current on start up which can easily be 5 times the running current on some machines especially those with speed up belt drives and/or 2 pole motors. The solutiuin is a mix of higher rated MCBs or as you have found using ones rated for motors ie Type C. Your sparky should have known that but so many just do standard domestic work and their knowledge can be weak when it comes to motor related analysis.

 

[craigs]

The reason higher rated MCBs are called for is the inrush current on start up which can easily be 5 times the running current on some machines especially those with speed up belt drives and/or 2 pole motors. The solutiuin is a mix of higher rated MCBs or as you have found using ones rated for motors ie Type C. Your sparky should have known that but so many just do standard domestic work and their knowledge can be weak when it comes to motor related analysis.

Oh he freely stated this isn't his normal kinda work, he really only deals with domestic stuff and doesn't really come across induction motors very often at all.