Electrical testing on Machines

[Tonkolili]

The company i work for manufactures machinery which have a control panel that houses all of the switchgear,inverters starters, PLCs etc, we carry out the electrical install on the machine but when it goes to the client, we are not responsible for the mains supply to the control panel, what i want to know is what are the regulations on testing the Earth Loop impedance etc on production lines. My opinion is that when we install the machine (when i say machine its actually a production line) we should carry out a full electrical test and inspection as you would on any installation, most of the circuits are Motors,Lighting,safety circuits and instrumentation. I have encountered this before where no testing is sort by the client or anybody when installing machinery, it seems to be the opinion that it is just the fixed wiring of a building that requires testing ??? any comments would be appreciated

 

[Farmelectrics]

why dont you ask for an eic on the supply cable to your machine

 

[Farmelectrics]

every electrical circut will have or should have an electrical test cert have you asked for them,. why would you want them if your just supplying the machine

 

[davesparks]

He's asking if they should certify the circuits that they install when they install the machine

 

[Farmelectrics]

well then the answers yes

 

[Darkwood]

Whoever installs the supply will cert' it for compliance, whoever installs the machine only need to clarify before energising that everything is sound and Zs is good of the supply as is the duty of anyone energising a new install, although I'd recommend there be a section in the commisioning paperwork to confirm its been checked and passed.

The machine supply is classed as part of the fixed wiring of the building so like all circuits it requires testing, the equipotential bonding and earthing of the building also requires confirming.

 

[Knobhead]

And here in lies a problem, advice given by domestic electricians regarding industrial matters.

 

[LeeH]

Are you asking if you can apply 7671 after the isolator on your 'machine' exactly like you do on the fixed wiring?

If so the answer is no, it's not possible to calculate or measure the EFL through the DC bus on a VFD. The manufacture will guarantee a disconnection time under fault. Ask them.

Circuits that are DOL can be as you can get the tripping curves for motor overloads from the manufacture such as Telemec/Schneider overloads.

Cable CCC's and installation methods can also be lifted from 7671 but 60204 needs to be your main focus.

 

[LeeH]

I'm sure Tony and others can add much more.

 

[Knobhead]

I know I wouldn’t like to get the machine going after someone had tried testing to BS7671 compliance. Testing the supply is about it.

 

[Bobster]

All outgoing power circuits are tested to bs7671, as stated a loop test is not possible with a VSD powered circuit. Most drives have built in thermal/SC & earth leakage protection. Along with other forms of protection.

 

[netblindpaul]

The fixed install must be tested to BS7671, the assembly of machinery must be proven in accordance with the statute law, e.g. SMSR as your company is CE marking the production line in accordance with their statute law duty.

 

[LeeH]

Don't see why you cannot use the dead tests from 7671. You don't have to wait until the field cables are terminated into the rail before you do them.

As the manufacture you would have to provide proof of the integrity of the install even if it falls outside of 7671. I think plucking things from the BYB would go a long way to showing that. And you could inset that into the mandatory technical manual?

To the OP, does your company not provide ANYTHING after an installation?

 

[netblindpaul]

Don't see why you cannot use the dead tests from 7671. You don't have to wait until the field cables are terminated into the rail before you do them.

As the manufacture you would have to provide proof of the integrity of the install even if it falls outside of 7671. I think plucking things from the BYB would go a long way to showing that. And you could inset that into the mandatory technical manual?

To the OP, does your company not provide ANYTHING after an installation?

No, it would not, as BS7671 does NOT apply to machinery under the machinery directive, this statute law has it's own set of requirements.

 

[LeeH]

I know that Paul, I have already posted that.

But just because a set of tests are used in 7671 doesn't mean they cannot be applied elsewhere.

The OP's company build control panels and then install the field cabling that sees no verification and certification.

It's not just a machine built to 60204 and wheeled onto the factory floor.

 

[Darkwood]

The machine install itself will still be subject to testing albiet via the relevant BS60204, when the controls are energised after install and dependent on the machine design and layout as to what requires testing the Annex A of the BS60204 explains all the required testing procedures and confirmations and yes it does somewhat mimic the BS7671 in some of its wording or vice versa (chicken or egg).

On installation you still have to ensure the integrity of the electrical system you have just fitted again the extent of your testing is subject to machine/control design, exemptions do exist - Where the calculations of the fault loop impedance or of the resistance of the protective conductors are available and when the arrangement of the installation permits the verification of the length and csa of the conductors, verification of the continuity of the protective conductors can replace the Zs measurement.

Even having motors running of drives where you cannot do a practical measurement then you will still need to confirm the continuity of the protective conductor.

If you are as in the OP situation installing a machine line then it would almost definately be subject to required testing procedures if the OP expresses these are not been carried out then the installers or those commisioning the production line are not doing what is required to sign the system over.

 

[LeeH]

Exactly the point I was making dark wood.