2. cables
  3. 193634-117492

confused about 20 amp power cables

I've recently acquired a pre-owned T+A PA 3100 HV integrated and this is my first exposure to a 20 amp power cable. The supplied cable has what I think is a C19 IEC connector (20 A) on the amp end, but the connector on the wall side has parallel hot and neutral blades as opposed to the 20 amp T blades. Is that end really rated at 20A? 

I have a dedicated 110V 20 amp circuit with 20 A receptacles, but is about 10 ft from my equipment. I am currently plugging the amp's supplied cable into an Oyaide OCB-1 SX V2 power conditioner which is plugged into the 20A wall receptical. The wall plug on the Oyaide appears to be a 15A plug and the  4 distributed receptacles are not 20A  and I assume they are rated for 15A. Is this dangerous to have this 15A section between wall and amp?

Would I be better off, or safer to find a 20A extension cable so I could plug the amp directly into the wall?  I've recently started building my own PCs and could make a 10 ft one with C19 on one end and 20A wall plug on the wall side ( ouch for wire cost for 10ft).  I know that its unlikely the amp will ever draw more than 15A. 

Any suggestions would be helpful!

128x128mintakax
williewonka
3,103 posts
 

@mintakax to start with, a cable with a 20 amp IEC and 15 amp plug is not conforming to north american electrical codes and should not be used.

Granted, it will work, but if there is ever a related shock or fire event, your insurance would probably void the claim.

Granted, the amp will probably never draw close to 20 amps continuous, but transient spikes may exceed 15 amps, which may explain why the amp has a 20 amp IEC socket.

To keep the "codes people" happy...

  • Put a 20 amp plug on the cable for the amp
  • Plug the amp into the wall.
  • If the cable is not long enough make a 20 amp extension cord.
  • Use the ocb-1 for other components and plug it into the same wall outlet

Re: the wall outlet: replace the outlet with a 20 amp hospital MRI grade outlet. It will grip the plugs very tightly and improve overall performance.

 

Regards Steve

ditusa's avatar
ditusa
1,918 posts
 

@williewonka Wrote:

@mintakax to start with, a cable with a 20 amp IEC and 15 amp plug is not conforming to north american electrical codes and should not be used

Not true! See here

Mike

williewonka
3,103 posts
 

@ditusa while you can clearly buy such a cable, for a receptacle  the code states...

  • A single receptacle installed on an individual branch circuit shall have an ampere rating not less than that of the branch circuit. 

So my interpretation is that the plug and socket on a cable should be of the same rating, because the cable is just an extension of that branch circuit.

I think it is one of those grey areas that will only be judged in the event of a catastrophic failure unfortunately.

Regards, steve

jea48
4,605 posts
 

@williewonka said:

A single receptacle installed on an individual branch circuit shall have an ampere rating not less than that of the branch circuit.

True, not less than. The single receptacle installed on an individual branch circuit can have an ampere rating greater than the ampacity rating of the branch circuit. Therein a single NEMA 5-20R (20 amp) receptacle can be installed on a 15 amp branch circuit.

As for this:

NEC 210.21 (B)(1)

.

@ditusa said:

@williewonka Wrote:

@mintakax to start with, a cable with a 20 amp IEC and 15 amp plug is not conforming to north american electrical codes and should not be used

Not true! See here

Mike

.

First, the discussion is in regards to a 15A male plug of a power cord with a 20 female IEC connector. NEC is not involved.

The power cord @ditusa Linked in his post may not be a Listed power cord. There are ones just like it manufactured that are Listed. UL Listed.

.

williewonka
3,103 posts
 

@ditusa - thanks for that info. Its interesting that UL allows this practice. Goes against everything I was taught in college in the UK, but that was some 50 years ago frown

So I guess it boils down to personal preference as to how safe a person would like to feel using a power cable of this design.

Personally, I would err on the side of caution and change the plug to a 20 amp model.

Regards Steve

 

 

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