Daikin outdoor main supply MCB triped

[sachin230]

I have Daikin 28hp, VRVIII system with 13 indoor units.Before 15 days , outdoor main supply MCB triped due to that all indoor units remote shows "U4" error.switch on the supply, system running satisfactory.

Today also outdoor unit main MCB triped.I dont understand wheather it was voltage flucution fault or there is problem in outdoor model due to that main supply MCB trip.

please sugest, which is the possible reason for outdoor Main supply MCB triping.

[ktm]

What size is the mcb? Does it trip at a particular time of day? Have u seen all comps and fans run?

[sachin230]

What size is the mcb? Does it trip at a particular time of day? Have u seen all comps and fans run?

thanks for reply

Legrand make MCB specification :415v,C63 Icu -10000ka,10KA &
another attached 0.1A,100mA

No it is not trip at particual time ( may be at starting period)

I have not seen all comps and fans run

[ktm]

Try run system on full heat or full cool so all the fans and comps will run. Could b a problem with a fan or one if the compressors. No water in the isolator switch?

[monkey spanners]

The thing that trips, is it a MCB or an RCD?
The 100ma makes me wonder if it is an RCD and its tripping due to earth leakage currents caused by the inverter circuit.

Is the a new installation or has it been working for a while?

Jon :)

[sachin230]

Thanks jon
this is new installation before one year but this problem start from last one month.(four different times supply mcb tripped)
I think It is RCBO

[monkey spanners]

I think inverters can make rcd's trip even when working correctly, it would help if you could fine out whether it was over current or earth leakage that was causing the tripping.

[sachin230]

Please guide me How to find the inverter leakage current and earth leakage.?
what is the procedure to find the invertor leakage current and earth leakage?

[sachin230]

your feedback much appreiciated

[monkey spanners]

Please guide me How to find the inverter leakage current and earth leakage.?
what is the procedure to find the invertor leakage current and earth leakage?

I don't know! Its not a problem i have seen personally.

[DTLarca]

Here are notes I put together for a level 3 lecture on electrical safety.

RCD Ratings other than the standard 30mA

•100mA
–Socket outlets of rating exceeding 32 A in agricultural locations.
•300mA
–At the origin of a temporary supply to circuses etc.
–Where there is a risk of fire due to storage of combustible materials
–All circuits (except socket outlets) in agricultural locations.
–Inverter drive systems such as found on AC systems.
•500 mA
–Any circuit supplying one or more socket outlets of rating exceeding 32 A, on a construction site.

[javed]

you should check machine indoor and outdoor unit communication wire.
i had same problem .

[sachin230]

Is your problem solved ? how?

I checked indoor unit and outdoor unit communication it is ok.

sometimes RCBO triped, & due to that indoor unit shows "U4"error.

Tripping not continous.where to arrest the the problem

[DTLarca]

Is your problem solved ? how?

I checked indoor unit and outdoor unit communication it is ok.

sometimes RCBO triped, & due to that indoor unit shows "U4"error.

Tripping not continous.where to arrest the the problem

This is your problem Legrand make MCB specification :415v,C63 Icu -10000ka,10KA &
another attached 0.1A,100mA

[sachin230]

I dont understand (100MA )

[DTLarca]

The RCD or RCBO is designed to be sensitive to 100mA leakage current - you need one rated at 300mA because the leakage current caused by an inverter for used on mini plits and VRV system is up nearer 200mA at peak.

If your system's loop impedance could permit the breaker to still trip within the time stipulated by your regulations or your earthing system was unreliable then you would not even use a breaker but would be forced to use an RCD or RCBO. In which case it should be selected for 300mA leakage current.

[wozza]

How often does it trip? once a day once a month? It sounds to me like a compressor.
If it is dooing it every couple of days and the load on the system is, it would make sennse.

[sachin230]

It trip once a month