RCD tripping when inverter running

[Kram]

its not nonsense reason being fitting wylex breakers in to a volex db they will fit yes but if there is an accident or the db sets on fire who is to blame wylex or volex then insurance companys wont pay out and your left hi and dry. each manufacturer makes the different types of rcd to fit in to there boards if u do want to fit a mismatch just put it in to a separate enclosure and it then doesnt matter

If thats the reasoning it is silly, should be a standard compatable fitment. However I respect that is the rule and in the electricians standards and I dont suggest anyone mess about with that.
Fitting to another enclosure will not work unless that enclosure has no upstream RCD.

RCD will have a symbol on it.

 

[Beavertooth]

Definitely RCD, not MCB? An MCB trips when over load, but an RCD trips when there is a leak to earth. The latter, of course, is a far more serious issue...

A pick of the breaker would be helpful.

Ok, It must be lockdown, but I just realised what you asked me for. So I am attempting to post 2 photos of my breaker box and the RCD so you can see what trips.

 

[Kram]

Can you tell us when it trips, instantly, when running, when it heats up, on stop?

Which VFD?

You have a 100ma and a 30ma RCD in there. If either of the last breakers on the right are sockets (15A or 30A) that would be worth a test as the trip current is 3x higher. If that works Id say still needs further investigation. 100mA RCD wont protect you as well if it does develop a fault!

 

[carbon]

That looks like an AC type and from the list I linked to earlier it’s not suitable for a vfd inverter. Changing it to a type A should work but someone with more experience hopefully will confirm

 

[Beavertooth]

I didn't get a chance to test it today, so will do it in the morning and update you all.

 

[Kram]

That looks like an AC type and from the list I linked to earlier it’s not suitable for a vfd inverter. Changing it to a type A should work but someone with more experience hopefully will confirm

While thats true, when my DB was recently replaced the sparky put an AC type in which I was not happy with, but no problems so far, it is a Contactum branded. I found Wylex A types work too, and now have 3 spares.

The invertek manual states a B type MUST be used and should not be shared with other stuff. Annoyingly it gives no reasoning. When I spoke to their tech support the guy did not seem qualified to answer and just said its to prevent tripping.

Rapidelectronics were the cheapest when I looked for a B type but it was still not cheap.

 

[Pete.]

I thought type A, B, C etc only related to the overload type, not the earth leakage facility.

 

[Kram]

RCD's no, they should never trip on overload.
RCBO's yes they have both MCB type and RCD type attributes which are rarely listed.

 

[Beavertooth]

OK, so I finally got to test my inverted motor again. The outcome is a confusing as the problem. So test 1 in the workshop: RCD trips. Test 2 in the house: RCD trips. However, when we isolated the consumer unit in the workshop and the shed, the house powered up the motor/inverter 100%. I tested it several time, forwards, reverse, tried to hold the wheel to simulate under power, even started it set at full RPM. All tests work fine and no trips. As soon as the trip in the shop or shed were put on, TRIP!!!!. So, what does that mean??

 

[Seadog]

Duff RCD?

 

[Kram]

I assume the pic above, is the unit in house. Which circuits go to shed/workshop, and what do they have?
Was everything in workshop unplugged?

 

[Onoff]

OK, so I finally got to test my inverted motor again. The outcome is a confusing as the problem. So test 1 in the workshop: RCD trips. Test 2 in the house: RCD trips. However, when we isolated the consumer unit in the workshop and the shed, the house powered up the motor/inverter 100%. I tested it several time, forwards, reverse, tried to hold the wheel to simulate under power, even started it set at full RPM. All tests work fine and no trips. As soon as the trip in the shop or shed were put on, TRIP!!!!. So, what does that mean??

Are the RCDs thd same make and rating?

The only way to properly test an RCD is with a dedicated RCD tester, ideally one incorporating a "ramp" test.

So your basic RCD "trips" when the earth leakage current exceeds 30mA.

Appliances, cables etc can all themselves be a little bit leaky to earth but not so much as to trip an RCD on their own.

It's likely an accumulation thing when plugged in at the shed end. Maybe some damp in the supply cable causing some leakage PLUS that of a still plugged in other appliance PLUS the inverter itself. Added up it's enough to trip the RCD.

All pretty moot tbh. Ideally you want a proper RCD tester along with insulation resistance tests on the cables.

 

[brightspark]

a combination of all your appliances could be putting the rcd over its leakage limit along with poor readings on the installation. a 30ma trip will trip if the leakage is over 20ma .kettles emersion heaters and cooker elements all give off leakage and electronic transformers on small apliances

 

[mtt.tr]

[QUOTE="Kram, post:
I would try a different RCD, which sparkies might frown upon, as there is some nonsense about not mixing brands.

i

nonsense reason being fitting wylex breakers in to a volex db they will fit yes but if there is an accident or the db sets on fire who is to blame wylex or volex then insurance companys wont pay out and your left hi and dry. each manufacturer makes the different types of rcd to fit in to there boards if u do want to fit a mismatch just put it in to a separate enclosure and it then doesnt matter

And the busbar offsets vary.

 

[brightspark]

here https://www.test-meter.co.uk/blog/18th-edition-new-requirements-for-nuisance-rcd-tripping/ . I have a clap meter that measures milliamps and use it if I cant determine earth leakage with the megger

 

[mtt.tr]

They rcd type rating is not for this reason infact its total opposite.

The rating is to prevent dc saturating the core which would prevent the rcd from tripping from ac leakage

 

[WorkshopChris]

As soon as the trip in the shop or shed were put on, TRIP!!!!. So, what does that mean??

Have you tried this with all the MCB's turned off Except the circuit you are running the inverter on.

 

[brightspark]

Have you tried this with all the MCB's turned off Except the circuit you are running the inverter on.

that would help but the neutrals are still all connected and anything down will detect imbalance

 

[mtt.tr]

that would help but the neutrals are still all connected and anything down will detect imbalance

Would cut down other appliances added a leakage current

 

[brightspark]

Would cut down other appliances added a leakage current

while running yes but not on an insulation test