Storage Heater Insulation Resistance

[studentspark]

Four new storage heaters

Instructions say The Dielectric IR at 500v must be at least 0.5Mohms

Im getting 2Mohms , L- E, and N-E on three of them, and 0.6Mohms on the other.

This is testing the heaters alone, not wired to the supply.

Are these IR results to be expected. They seem very low, especially L-E

Thanks

 

[JohnD]

Which resistance is higher?

0.5MΩ or 2.0 MΩ?

 

[John D v2.0]

Are these IR results to be expected. They seem very low, especially L-E

According to the instructions, yes. But you could call the technical line to clarify. They seem low to me too, but maybe there's a technical reason for it, hence why they documentsd such a relatively low value

Which resistance is higher?

0.5MΩ or 2.0 MΩ?

2.0M of course, why do you ask?

 

[Lectrician]

Elements kept in storage for some time will absorb moisture, also from manufacture. After a few days of use the moisture will be driven out and the readings will improve.

 

[crystal ball]

Are you testing from the incoming terminal block, are all your input controls set to max, the element casings are not in contact with earth apart from possible contact with the bricks, and then through the insulation

 

[studentspark]

I was wondering if there was some electronic component, a suppressor or such to reduce noise?
Have no idea on electronics , so could be talking nonsense.

Yes testing at the incoming terminals.
Thanks for the suggestion

 

[crystal ball]

Some heaters have an accelerator heater on the bi metal strip / flap control, I assume these are standard heaters and not the new all singing type

 

[studentspark]

Yes, Standard heaters , not the new electronic thermostat controls. Manufactured by Olsberg

 

[ban-all-sheds]

2.0M of course, why do you ask?

Instructions say IR must be at least 0.5Mohms, is 2M and 06.M OK?"

 

[studentspark]

Putting large metal boxes in every room, you would want them to be properly earthed, and a value of 0.5mohms on an appliance would concern me.
The manufactures state this as a minimum. I was more interested in the reasons for the low IR values.

 

[ban-all-sheds]

Putting large metal boxes in every room, you would want them to be properly earthed,

They will be if installed properly.

and a value of 0.5mohms on an appliance would concern me.

What's the worst case fault current?

The manufactures state this as a minimum. I was more interested in the reasons for the low IR values.

As per Lectrician - run them for a few days and test again.

 

[studentspark]

Yes I plan to, thanks