240v Control Curcuit

[Nazza]

Our company is working on a piece of machinery which has come from China.
We are ensuring the electrics are safe.

The control side of the electrics is 240v. All the components in the system are CE marked and from reputable brands.

1 electrician says we should remove all the control system and replace for 24v.

Another says the control system is fine at 240v as long as it is wired up correctly.

The machine is a fairly simple wrapping machine. Functions on the control curcuit include on of buttons etc.

We have been reading the machinery directive and the low voltage directive and all we can find is the phrase "it should be intrinsically safe"

So, my question is whether 240v in a control circuit could be considered safe and legal providing it is wired up correctly and the componenets are reputable brands with CE marks.

 

[Antony1]

I was just referring to the stand alone wall mount type, just showing an example where 230v control is used

 

[Pete999]

I was just referring to the stand alone wall mount type, just showing an example where 230v control is used

OK right must have misunderstood your statement, sorry

 

[Bobster]

I was just referring to the stand alone wall mount type, just showing an example where 230v control is used

These aren't classed as a control system under EN60204 and thus don't need to meet there requirements as they are simple apparatus.

This is why you can still buy them with 400v control.

 

[Antony1]

These aren't classed as a control system under EN60204 and thus don't need to meet there requirements as they are simple apparatus.

This is why you can still buy them with 400v control.

I thought they where?

EN60204
"Transformers are not mandatory for machines with a single motor starter and/or a maximum of two control devices (for example interlock device, start/stop control station)."

Although the coil voltage is 400v, the control circuit is 230v.

I think I'll be much clearer in my response next time as I seem to have been misunderstood

 

[Pete999]

I thought they where?

EN60204
"Transformers are not mandatory for machines with a single motor starter and/or a maximum of two control devices (for example interlock device, start/stop control station)."

Although the coil voltage is 400v, the control circuit is 230v.

I think I'll be much clearer in my response next time as I seem to have been misunderstood

I'm not sure I understand, 400v coil 230v control circuit, how does that work or have I totally misunderstood what you are saying?

 

[Antony1]

Well the voltage is 230v at the start and stop button, overload etc so the bit that controls it is 230v just my opinion

 

[Darkwood]

Seems to be a lot of confusion on this matter of 230v control circuits, so hopefully I can simplify it for you and put this thread to bed.
Under the BS60402-1 the requirements state that if machinery(control system) has more than 2 actuators ie.. E-stops, limit switches etc then the control voltage must be of an isolated nature, this basically means that whatever the voltage may be it must be done through an isolating TX, where the control has less than 2 actuators then direct mains voltage control is fine hence you can buy a DOL starter with 400v, 230v coils wired directly to the supply of the installation.

I think the intrinsically safe debate has been resolved earlier but that has nothing to do with the content of this discussion and would only really come into play in say an explosive environment or similar hazardous areas.

This is one of the main breaches of regulation found when using 230, 400 control systems in that someone will be asked to add a few more e-stops or a safety limit switch etc and they leave the exiting direct voltage circuit in place not realising their actions has changed the reqiurements of the circuit under the BS60402-1.

As for China - unless the company has world wide good reputation and a high regard for local regulations of the target market then trust no-one, they fake falsify and rip off people at an astoninshing level, any company importing and reselling such goods needs to employ a 3rd party to test, conform compliance and stamp any CE/EC marking themselves, just had a batch of pumps with all the paperwork supplied from china through a uk intermediate company that had a lable saying it must comply to the 18th edition BS7671 !!!!... sent them all back and all the company supplying them could say was they have the right paperwork although they now know where their responsiblities lie after a email chat with me....

 

[Pete999]

Well the voltage is 230v at the start and stop button, overload etc so the bit that controls it is 230v just my opinion

What about the coil? @400v the 230v control isn't going to pull it in.

 

[Antony1]

What about the coil? @400v the 230v control isn't going to pull it in.

It sure will if there is a different phase connected to the A2, the control circuit is the same wether it is a 230v or 400v coil the only change is the connection to the A2 of the coil

 

[Pete999]

It sure will if there is a different phase connected to the A2, the control circuit is the same wether it is a 230v or 400v coil the only change is the connection to the A2 of the coil

So you are saying it's a 230v control circuit with a 400v coil? to me that's a 400v control circuit

It sure will if there is a different phase connected to the A2, the control circuit is the same whether it is a 230v or 400v coil the only change is the connection to the A2 of the coil

If the control circuit is connected across 2 phases then that control circuit will be deemed a 400v circuit, L1 at the start of the control ending up at A1 on the coil at A2 the other end of the coil is connected to either L2 or L3 the circuit will be 400v, if you have a coil rated at 230 v then A2 should be connected to N.

 

[Antony1]

400v circuit voltage but 230v control voltage, I'm sure you see my point and I see yours like I said before it's just my opinion

 

[Pete999]

400v circuit voltage but 230v control voltage, I'm sure you see my point and I see yours like I said before it's just my opinion

In your case then what rating is the coil? what is the A2 of the coil connected to? Where are you measuring 230volts on your control circuit?

 

[LeeH]

I don't understand either Pete, it's one or the other unless you are pulling in the contractor via a 230 relay with 2 phases through it. Which obviously would be silly.

It's one or the other.

L1 at the start or the circuit, through the latch to the coil and N at the end 230V
L1 at the start of the circuit and L2 at the end 400V

 

[Lagentium]

I guess the stop and start buttons etc will only have 230v to them, these must energise a relay or suchlike which then connects the other phase for the 400v coil to pull in. With the relay situated in the panel. Thoughts?

 

[Pete999]

I guess the stop and start buttons etc will only have 230v to them, these must energise a relay or suchlike which then connects the other phase for the 400v coil to pull in. With the relay situated in the panel. Thoughts?

This is getting stupid, L1 to start of control circuit ends up A1 on coil (400v rating) A2 to L2 or L3 400volt control circuit.
A1 to start of control circuit ends up A1 on coil A (230 V coil rating) A2 to N 230v control circuit and so on with differing voltages i,e, 12v 24v 50v 100v 150v etc its not rocket science fer Christs sake. Obviously the lower voltages will require a transformer of some sort. I take it you do realise you can swap the coils around to suite your needs, please say yes.

 

[LeeH]

I guess the stop and start buttons etc will only have 230v to them, these must energise a relay or suchlike which then connects the other phase for the 400v coil to pull in. With the relay situated in the panel. Thoughts?

View attachment 35489

 

[davesparks]

It sure will if there is a different phase connected to the A2, the control circuit is the same wether it is a 230v or 400v coil the only change is the connection to the A2 of the coil

It will be 240V to Earth, but it is not working to earth, it is working between phases and so it is 415V.
You don't install a machine which uses a 415V 2phase supply and call it a 240V supply.

If the cool is operating at 415V then the start contact will have 415V between its terminals when it is open, how on earth can that be 240V control?

 

[netblindpaul]

The OP has had the technically correct answers on the IET forum, but, has up until this point in time ignored them.

 

[davesparks]

Under the BS60402-1 the requirements state that if machinery(control system) has more than 2 actuators ie.. E-stops, limit switches etc then the control voltage must be of an isolated nature, this basically means that whatever the voltage may be it must be done through an isolating TX, where the control has less than 2 actuators then direct mains voltage control is fine hence you can buy a DOL starter with 400v, 230v coils wired directly to the supply of the installation.

What constitutes and actuator? Does this mean that a simple DOL starter with three buttons on it (start, stop, reverse or inch) would have 3 actuators?

 

[netblindpaul]

The OP has had the technically correct answers on the IET forum, but, has up until this point in time ignored them.

What constitutes and actuator? Does this mean that a simple DOL starter with three buttons on it (start, stop, reverse or inch) would have 3 actuators?

No, if they are in one enclosure then they are one "device".
Don't forget once you go from simple systems into safety devices, emergency stops, guard switches, light curtains etc. then you are into full blown EN 13849 territory and that is required for compliance with the SMSR & PUWER, and anyone doing this work is encompassed into this legislation.

 

[davesparks]

No, if they are in one enclosure then they are one "device".
Don't forget once you go from simple systems into safety devices, emergency stops, guard switches, light curtains etc. then you are into full blown EN 13849 territory and that is required for compliance with the SMSR & PUWER, and anyone doing this work is encompassed into this legislation.

Thanks, I'm only curious as to what point a simple system stops being simple.

 

[Lagentium]

Don't worry Pete, I don't need educating, I was just trying to grasp what the bloke said as I couldn't understand it.

 

[netblindpaul]

Thanks, I'm only curious as to what point a simple system stops being simple.

Once you have a safety function, so basically anything more than an e-stop, and more than the device count as specified in EN 60204-1.

 

[davesparks]

Once you have a safety function, so basically anything more than an e-stop, and more than the device count as specified in EN 60204-1.

Personally I just turn down any work which involves motor/machinery controls, but I do wish that at some point during my time at college someone had actually told us that these regulations even exist and told us what the average electrician can and cannot do without further training.

 

[LeeH]

Grab a copy of 60204 Dave, it's relatively an easy read compared to the BYB.

 

[davesparks]

Grab a copy of 60204 Dave, it's relatively an easy read compared to the BYB.

I was under the impression it was a tad expensive?

 

[LeeH]

It makes 7671 look a bargain.

PM sent.

 

[Bobster]

EN60204 is relitivly cheep, problem is going any deeper than the surface requires other standards like EN12100, E13849-1 & EN62061 being the main ones.

Looking at circa £550 for those 3 if you're not a BSI member.

 

[LeeH]

It's over 200 IIRC.

 

[Bobster]

60204 is £282 from BSi if you're not a member £141 if you are.