Hi guys, I'm new to AAC. I reside in Malaysia which is currently running 220-240V mains voltage. I purchased a Toyozumi Step Down to operate 100V amplifiers I bought from Japan. This is the specs (I took it from the seller's site so have to remove the wordings):

As seen from the picture, I'm stuck at the 2 'grounds' connections. I referred here: https://incompliancemag.com/article/the-grounding-symbols/
I am uncertain to establish the connections so I need some clarifications before:
- The chassis ground (left) just like the name indicates, connects to the chassis /case in which the metal is enclosed?
- The protective earth, connects to where?
- 0 terminal should be connected to neutral?
- I want to place a circuit breaker (ELCB) before the primary, I use the calculations below to get amperage:
P=VI (PRI)
1800 = 230 * I
I=7.8A/ 8A

Is it the correct way to determine breaker amperage?

- I am placing another ON-OFF switch at the primary. Should I switch off the live (hot) wire only or both neutral and live?

Thank you for assisting me and have a nice day

 

Try something like this...

All the ground/earth connections go together on the metal case.
I would put a 12Amp breaker as the overload. It may still pop with the turn on surge but try and see.
And use a double pole power switch and switch both the input active and neutral.

 

Hi dendad, thanks for your guide. I still got confused at the earth connections.
When you said 'All the ground/earth connections go together on the metal case', do you mean:

 

NO.
Mains cable Earth All the terminals in the yellow/green strips.
NONE of the power terminals!!!!!!!
Look at my circuit.

 

NO.
Mains cable Earth All the terminals in the yellow/green strips.
NONE of the power terminals!!!!!!!
Look at my circuit.

Yes, I agree. The connections I posted only involved two terminals in yellow/green strips like you said. The neutral and hot wires are not wired using ground. Perhaps it was the words get mixed up with the wiring. I should have used proper wording rather than 'self-write' , apologies for that .

I went through the your circuit.
This is my understanding:
- the chassis (metal case) and transformer grounding terminal goes to one same point which is the mains grounding or so called "E"

Am I right on this?

 

That transformer is 15 amp that's 7.5 amp Pir I'd use a 10 breaker 12 amp lets you get 24 amp on the sec side that's about 5 amps to much if you like the transformer

 

It should be verified, but normally the yellow-green DIN rail blocks electrically connect the terminals to the rail by their mounting mechanism.

 

Yes, as ebp points out, I should have mentioned the "G" DIN rail terminal blocks usually do go to the DIN rail via the center screw, so are already connected to the metalwork. Make sure the screw is tightened.
And sorry for the confusion. I tend to use "Earth" instead of "Ground".

 

It means to say that both yellow-green terminals are linked together via the rail, there is no need to insert a jumper wire between them but it is still necessary to establish connections for the terminals.

In this case:
chassis ground connects to chassis
grounding terminal connects to mains earth

So the chassis is still wired to the mains earth, indirectly via rail.

Am I right on this?

Another question, the grounding from power outlets (I am planning to wire 4 outlets) , is the connection going to grounding terminal as well?

 

All the terminals of the yellow/Green strips are connected together and to the chassis.
I would probably connect the 2 strips together with a link anyway just for added safety but it is probably unnecessary.
Usually it is regarded as good practice to have the mains grounds run in wires too just in case a mounting screw is not tightened well.

 

Alright guys, thanks for the help

Cheers,
Jeremy

 

ebp is right, both terminals are connected via center screw. I had a chance to verify it today. The multimeter shows a very low resistance reading.

 

Hey guys! Sorry to revive this old thread.
I want to verify the live and neutral connections for the transformer.

Live wire connection- The terminals having voltage values:
240v, 230v, 220v, 208v, 200v, 100v, 110v, 115v, 120v

Neutral wire connections- terminals labelled '0':
0 at primary
0 at secondary

I want to use multimeter to check the output voltages as well.
POS- LIVE
NEG- NEUTRAL
both positive and negative probes can be reversed, right? Since it's AC supply.

Here's an example:
https://drive.google.com/file/d/1lVwBFP0ovVOAOQDqQqp7Go56GDEYQuSh/view?usp=sharing

 

NOT Neutral to 0V secondary!!!
The primary and secondary are not to be connected together in normal use.
Look again at my circuit.