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Anonymous Poster #1

Dielectric Test Voltage for Auxiliary / Control Circuits

11/07/2012 1:28 AM

IEC 60439-1 states that Dielectric Test voltage AC for a Control circuit whose rated insulation voltage (Ui) is less than 60V must be [2Ui + 1000 with a minimum of 1500].

Now there is a Switchgear with Control circuits containing timers and relays and the cable is 2.5 mm2 ,1000v PVC cable.

the question bothering me is how can the control circuit of this switchgear withstand the test voltage as stated by IEC.

As far as my knowledge goes, a panel assembler / integrator doesn't really conduct dielectric test on the control cable. they do it only for Busbars or main Power Cables.

dielectric test on the control cable is done in their respective factories.

Any help on this matter is highly appreciated.

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Guru
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#1

Re: Dielectric Test Voltage for Auxiliary / Control Circuits

11/07/2012 3:18 AM

Where is it stated that this test must be carried out?

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Anonymous Poster #1
#2
In reply to #1

Re: Dielectric Test Voltage for Auxiliary / Control Circuits

11/07/2012 3:40 AM

IEC 60439-1, 8.2.2.4.2, Table - 11

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Guru
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#7
In reply to #2

Re: Dielectric Test Voltage for Auxiliary / Control Circuits

11/07/2012 5:00 AM

Is this test applicable to installed cables outside the panel only, or is it applicable to inside the panel as well (unable to find source copy of the standard here)?

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Anonymous Poster #1
#9
In reply to #7

Re: Dielectric Test Voltage for Auxiliary / Control Circuits

11/07/2012 5:55 AM

they haven't specified a particular field. But since they have mentioned Control / Auxiliary Circuits in the IEC, my client is insisting on this matter.

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Guru
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#11
In reply to #9

Re: Dielectric Test Voltage for Auxiliary / Control Circuits

11/07/2012 9:43 AM

That answers the question. Follow the Client's instructions.

If the cable survives the test, then fine. If it doesn't, then change it for one that does.

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#12
In reply to #11

Re: Dielectric Test Voltage for Auxiliary / Control Circuits

11/08/2012 4:46 AM

In the 20 years of Business, we never have done such a test. I have not even heard of any panel maker conducting such tests. Have You?

what i wanna know is does anyone have any experience with this test.

My A$$ is on fire. please Help.

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Guru
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#16
In reply to #12

Re: Dielectric Test Voltage for Auxiliary / Control Circuits

02/04/2025 7:07 AM

Ask for training.

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#3

Re: Dielectric Test Voltage for Auxiliary / Control Circuits

11/07/2012 3:58 AM
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Anonymous Poster #1
#4
In reply to #3

Re: Dielectric Test Voltage for Auxiliary / Control Circuits

11/07/2012 4:09 AM

It doesn't answer my question

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Guru

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#5
In reply to #4

Re: Dielectric Test Voltage for Auxiliary / Control Circuits

11/07/2012 4:40 AM

My apologies.

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#10
In reply to #4

Re: Dielectric Test Voltage for Auxiliary / Control Circuits

11/07/2012 6:44 AM

how com the cable support that voltage? It does not. your answer...

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#13
In reply to #4

Re: Dielectric Test Voltage for Auxiliary / Control Circuits

11/08/2012 10:13 AM

Maybe this will help.

The test you are refering to is a "one-time" acceptance test, that is designated for new cables coming off the assembly line prior to being put in service.

It can be a very destructive test especially if used more than once for field checking of cables and/or any electrical equipment/devices after their installation.

It is not and never has been an accepted test for assembled control panel wiring and devices and it will damage or destroy any equipment the conductors are attached to.

As already stated; If your client is demanding this test it is imperative that all of the cable condutors to be tested are completely isolated from the panel equipment and field devices.

You really need to make sure they are aware of the associated risk and if I were you I would get a waiver of liability signed off by their management before proceeding.

Review the IEE electrical device testing recomendations if you want to know which test is acceptable for your particular application.

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Anonymous Poster #1
#14
In reply to #13

Re: Dielectric Test Voltage for Auxiliary / Control Circuits

11/11/2012 4:17 AM

"It is not and never has been an accepted test for assembled control panel wiring and devices "

i Totally agree with u ....please can u give me any reference / supporting document .

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Guru

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#6

Re: Dielectric Test Voltage for Auxiliary / Control Circuits

11/07/2012 4:52 AM

Since you have to comply with the code, follow it. Look for 2.5 mm2,1500v PVC cable then, or look for any exceptions permissible under the code.

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Anonymous Poster #1
#8
In reply to #6

Re: Dielectric Test Voltage for Auxiliary / Control Circuits

11/07/2012 5:53 AM

"exceptions" .That's where i require some help. i couldn't find any in IEC, if you have any reference for that i would be grateful. Also in the specification of that particular project it calls for 1000V cable. The testing Manager of the client is asking us to comply with IEC Testing standards.

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#15

Re: Dielectric Test Voltage for Auxiliary / Control Circuits

11/12/2012 4:08 AM

IEC 60694-Common specifications for high-voltage switchgear and controlgear standards

Ch. 7 Routine tests 7.2 Tests on auxiliary and control circuits

7.2.4 Dielectric tests

"Only power frequency tests shall be performed. This test shall be made under the same conditions as those detailed in 6.2.10.

The test voltage shall be 1 kV with a duration of 1 s.

ch.6.2.10:.......

"Normally, the test voltage of motors and other devices used in the auxiliary and control

circuits shall be the same as the test voltage of those circuits. If such apparatus has already

been tested in accordance with the appropriate specification, it may be disconnected for these

tests. Lower test voltage values are under consideration for auxiliary components. If it can be

verified that the dielectric stress permits it, lower voltage values may be used, by agreement

between manufacturer and user".

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