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i have a Combicon connector "2EDGK", its datasheet says its capacity rated as 300 volt 15 ampere AC, how much maximum current it can draw for 240 volt and 120 volt AC?

300 VOLT X 15 AMP = 4500 VA,

AMPERE RATING FOR 240 V= 4500/240=18.75 (RESISTIVE LOAD)???

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The math doesn't work that way -- the amperage limit is constant no matter what voltage you're putting in as it's set by the maximum permissible heating of the connector contacts. So it's still only good for 15A at 120/240VAC.

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  • \$\begingroup\$ here is a twist sir, i have a relay HJR-21FF-S-Z, datasheet says its capacity as 300 volt 7 amp, 240 volt 10 amp and 12 amp at 120 volt AC, why its current carrying capacity increased while decreasing voltage??? \$\endgroup\$ – Rakesh Roy Jul 18 '16 at 1:31
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    \$\begingroup\$ @RakeshRoy -- ask a new question \$\endgroup\$ – ThreePhaseEel Jul 18 '16 at 1:32
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    \$\begingroup\$ @RakeshRoy - probably due to eletric arc de-rating at higher voltages \$\endgroup\$ – Wesley Lee Jul 18 '16 at 2:00
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Each maximum rating is generally separate for power connectors. Without regard to current, the connector isn't rated to operation at more than 300VAC. Similarly, without regard to voltage, the connector isn't rated to operation at more than 15A.

Therefore, the maximum safe continuous current draw is 15A, either at 240VAC or 120VAC. This is why 220 or 240V is used for larger home appliances: you get more power (really VAR) for the same current over 120V.

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  • \$\begingroup\$ here is a twist sir, i have a relay HJR-21FF-S-Z, datasheet says its capacity as 300 volt 7 amp, 240 volt 10 amp and 12 amp at 120 volt AC, why its current carrying capacity increased while decreasing voltage??? \$\endgroup\$ – Rakesh Roy Jul 18 '16 at 1:31
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    \$\begingroup\$ A relay is not a simple connector and additional factors come into play. I have clarified my first sentence for this context. Increased current capacity at lower operating voltage in a relay may be related to the durability of the contacts. \$\endgroup\$ – user2943160 Jul 18 '16 at 2:08
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    \$\begingroup\$ @RakeshRoy additionally, it's fairly bad form to copy/paste the same comment in two places. As mentioned above, this is indeed a separate question that shouldn't be asked in the comments. \$\endgroup\$ – user2943160 Jul 18 '16 at 2:09

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