Air Conditioning system not Grounded

[FarangRimPing]

We recently had another couple of split air conditioning units installed at our house. A couple of days after installation, I touched one of the outside compressor units and got quite a strong tingle.  I measured the voltage to ground and then opened the unit and saw that no ground was connected. I then checked all of the other units, both old and new, and found the same thing. These units were installed by different companies, including Homepro, so it seems like this is standard practice. The most recent installer is supposedly the best in the area, charges twice as much as everyone else, and is in high demand.

 

I grounded the units myself so all is OK now but thought others on this forum might want to check their A/C units to ensure safety.

[bankruatsteve]

Did the electric supply not include ground wire?  If it didn't, it should have and they should have connected per standard practice.

[Peterw42]

OP, interested to know how you grounded the outside unit ?

As 99% of the time its only ever 2 wires from the indoor unit, even if its 3 wires the 3rd is often used for the inverter control. Nowadays unless they run 4 wires  from inside unit, there wont be an option to earth it.

 

[johng]

11 minutes ago, FarangRimPing said:

I touched one of the outside compressor units and got quite a strong tingle.

If you got a shock from the metal case then IMHO something is wrong it's not "normal"   just out of curiosity how many volts did you measure going to ground ?

 

11 minutes ago, FarangRimPing said:

I grounded the units myself so all is OK

So now you have a constant flow of "wasted" electricity  flowing to ground..yes its good that its not flowing through a person but the fault is still there   I would look for chaffed wires or joints/connections tapped up and touching the metal casing

look too at the wire that goes through the wall could be tapped up to the copper/aluminium coolant pipe and  was damaged during install or become leaky due to moisture or pest attack  ants, rats etc.

 

 

[worgeordie]

I had the same problem,when i discovered the earth wire

was just pushed inside the A/c, connected to nothing.no

wonder  many people die from electrical problems.

regards worgeordie

[Crossy]

IMPORTANT NOTE:

 

Getting a tingle from an ungrounded Class-1 appliance like your A/C or a desktop computer is NOT a fault.

 

All these appliances have a mains inlet filter which places capacitors between L,N and G. These form a capacitive voltage divider which will float the metalwork to about 50% supply voltage if the earth is not connected. Hence the tingle.

 

Connecting the ground wire drains this current to earth (along with all the nasties the filter takes out).

 

The current is tiny, certainly not lethal and it's not going to affect your power bill to any measurable extent.

 

[tifino]

... just like when 'floating chassis colur tv design became very popular back 40 years ago...  when we had fellow military fellas taking back their locally bought tellys home to Australia

- the first step they did was to hand the TVs in to our Radio Workshops on (RAAF)Base -  to have us install fully insulated 240v line power transformers into them... 

 

[Crossy]

There was a particularly nasty Philips/Pye set which had a bridge rectifier on the mains inlet and then the -ve of the bridge went to "0V". Of course this meant that 0V was actually half mains.

 

Connecting a grounded scope probe to said 0V was quite spectacular!

 

[FarangRimPing]

The 2 new compressors had to be placed on a 1 meter wide balcony, where people (including children) need to squeeze by them. Very difficult to get by without touching the units. That's why I wanted to eliminate the tingles.

 

No ground wires were present. Initial units were wired by the electricians when we had the house built. The new units were wired by the AC installers.

 

Before I grounded the compressors, the voltage to ground was about 20-25V. One reading showed over 100V but I think that the reading might not have been correct because the meter I used had old batteries which were failing.

 

I installed a ground rod for each compressor, and ran 6mm stranded wire between each unit and its ground. Now the measurements show about .5V to ground.

 

 

[johng]

22 hours ago, FarangRimPing said:

Before I grounded the compressors, the voltage to ground was about 20-25V.

 

Yesterday I cleaned my aircon  which is also not earthed !  obviously  it was switched off at the breaker and I had already established that the breaker was breaking the  live wire not the neutral.....  anyway before cleaning/switching off

I measured various points on the metal casing to ground and found from 1.5 to 3.8 volts AC

I have touched the metal casing in the past whilst live and not received any sort of shock ,it is located high up on the balcony  out of reach for kids but within reaching distance for adults so another job to add to the to-do list ????️  ????

[Led Lolly Yellow Lolly]

On 5/6/2021 at 10:52 AM, bankruatsteve said:

Did the electric supply not include ground wire?  If it didn't, it should have and they should have connected per standard practice.

 

'Standard practice' in my experience, where they DO bother with a ground, is to use a scrap 8 inches piece of copper coolant pipe from the install, ram it into the nearest patch of soil, wrap a piece of scrap wire around it (any colour will do) and then poke it under a screw of the compressor case.

[ExpatOilWorker]

It is important to have good ground, especially in the shower. I have just improved mine. Safety first!

 

 

[Yellowtail]

If you had HomePro do  the recent work, if you squeak they'll typically make it right.

[BenDeCosta]

When I built my computer, I got a mild zap from the case. I assumed that I had done something wrong or that the PSU was faulty, but it's normal here apparently. Most houses don't seem to have the metal rod buried in the garden, i.e. no earth.

 

If you want to make it safe, you'd need to get an earthing rod buried in the garden and wired up to the house.