Enquire about continuity testing

[k1gabi]

Today I've seen an installation which powered different recording professional sound equipment. The board had 10 circuits with 10 MCBs. Just as an enquire, when I measured with my multimeter the continuity between live and neutral on some circuits it gave me infinite as it should be, but on 3 circuits it gave me a reading of only 6 ohms or 10 ohms. Basically all the load equipments were connected to the circuits and of course the mains and MCB's were off. Can some equipments could potentially give a false multimeter reading, even they work fine ? When powered on, all the equipments were working fine...

 

[binky]

anything connected to a circuit will give false readings

switching off is usually nough to resolve any issues, but unplugging is far better.

 

[k1gabi]

anything connected to a circuit will give false readings

switching off is usually nough to resolve any issues, but unplugging is far better.

So, if the equipments were working fine, this could be a false reading ? What type of loads can give a false continuity reading like this one, bellow 10 ohms ? Ty.

 

[binky]

the idea of the testing is to test the cabling / circuits, not any equipment connected to it. Sounds like you are testing wrong having re-read your post. Continuity is usally done Live and earth, connect live and earth at the board end, (put ends in a connector block)  then take a reading at the end of the cct. I like to do N-E as well.  readings of 6-10 Ohms is a fail for most ccts. 

 

[SPECIAL LOCATION]

Today I've seen an installation which powered different recording professional sound equipment. The board had 10 circuits with 10 MCBs. Just as an enquire, when I measured with my multimeter the continuity between live and neutral on some circuits it gave me infinite as it should be, but on 3 circuits it gave me a reading of only 6 ohms or 10 ohms. Basically all the load equipments were connected to the circuits and of course the mains and MCB's were off. Can some equipments could potentially give a false multimeter reading, even they work fine ? When powered on, all the equipments were working fine...

There is no requirement to test continuity between Live & Neutral with a multimeter?

Why would you even do this?

Have you ever done any calculations with parallel resistors to see what the combined resistance value is?

:C     

 

[phil d]

As @SL says testing live to neutral with a multimeter is pointless, it won't reveal anything useful because you are only testing at a low voltage, the only time I do a low voltage continuity test like you describe is if I want to see just how bad a fault is, if you get a fault that shows up with a standard multimeter then you know it's a bad one. A point to remember with connected loads is that most stuff will have transformers in them and these will give a low resistance reading which is one reason why you make sure everything is disconnected when doing a test, if you are unsure you link live and neutral together and test between them and earth as there's less chance of blowing something up.