Question about 220 V supply with one circuit for 110V outlet.

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Vim

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Location
Imus, Cavite, Philippines
What is the correct approach here in this problem?

The normal voltage in our country is 220 v supply but my client wants to purchase an appliance from the US that is rated 110 V so I have to put a 110 v circuit to meet her needs. My plan is to use one breaker from the 220V panel that will feed the 220/110 transformer and its output will go to the 110V circuit. Should I put another panel for 110V or can I feed the 110V circuit directly from the transformer? An engineer said that I should put another panel for the 110V but I am thinking that is it a waste of panel if I only have one circuit for the 110 V? Any tips how to size up the wattage that I need for the 220/110 Volt transformer?

Comments and suggestions are welcome. Thanks!
 
You could do this: 10amp type D curve OCPD, 2.0 mm2 wire for the primary. 2000 va transformer (or 2500va if you they exist over seas), 3.5mm2 cable on the secondary grounding one leg on the side.
 
Be sure to consider frequency ratings and differences as well (50/60 Hz) if applicable.
 
Vim said:
What is the correct approach here in this problem?

The normal voltage in our country is 220 v supply but my client wants to purchase an appliance from the US that is rated 110 V so I have to put a 110 v circuit to meet her needs. My plan is to use one breaker from the 220V panel that will feed the 220/110 transformer and its output will go to the 110V circuit. Should I put another panel for 110V or can I feed the 110V circuit directly from the transformer? An engineer said that I should put another panel for the 110V but I am thinking that is it a waste of panel if I only have one circuit for the 110 V? Any tips how to size up the wattage that I need for the 220/110 Volt transformer?

Comments and suggestions are welcome. Thanks!
Click to expand...
Can't you get a transformer at the airport?
 
A transformer and sub-panel for a single 110 circuit may seem like overkill, until the customer wants a 2nd 110 circuit.
 
Jraef said:
Posted by someone who has no doubt been down that road before...

Better to have it and not need it than to need it and not have it.
Click to expand...
Not been down that road for wiring, but the same thing goes in computer programming-- plan for what they said they'll never need, plus some things you think they'll think of eventually!
 
I agree the subpanel is a great idea.
We need to know how many amps the 120V load is if you want help sizing the transformer.
And I will add the Philippines Electrical code is a slightly modified NEC,
I don't have a current version but in my old version however the section:
2.40.1.4:
Code: 
(f) Transformer Secondary Conductors. Single-phase (other than
2-wire) and multiphase (other than delta-delta, 3-wire) transformer
secondary conductors shall not be considered to be protected by the
primary overcurrent protective device. Conductors supplied by the
secondary side of a single-phase transformer having a 2-wire (single-
voltage) secondary, or a three-phase, delta-delta connected transformer
having a 3-wire (single-voltage) secondary, shall be permitted to be
protected by overcurrent protection provided on the primary (supply)
side of the transformer, provided this protection is in accordance with
4.50.1.3 and does not exceed the value determined by multiplying the
secondary conductor ampacity by the secondary to primary
transformer voltage ratio.

ARTICLE 4.50 — TRANSFORMERS AND TRANSFORMER
VAULTS (INCLUDING SECONDARY TIES) is pretty much the same as article 450 of the NEC.
And there is a nice little table much like ours:
i.png
 
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