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rize 10th October 2012 11:57 PM

Isolation Transformer - AC Plug question
For DIY projects, I bought a medical grade isolation transformer from eBay. The traf is made by Toroid. Not sure if Toroid is in business. They don't answer phones and don't reply to e-mails. Some of their pages on their web-site are not working.

Can anyone tell me what type of AC plug is required for the 4 AC receptacles fitted in the front panel?

Standard AC power cord with circular ground pin obviously doesn't fit. I assume the hospital equipment has different plugs than equipment designed for home use. The neutral and the hot conductor pins (unlike the std AC cord) has sockets of different shape and size. The front label states neutral conductor is not grounded hence the isolation from the Ground at the utility pane which is great but why disallow the use of standard AC power cord? I can use this traf with an improvised cord but not being able to use standard AC power cord is inconvenient. I'm thinking of changing the receptacles or find a place which sells suitable power cord. Thank you for your comments in advance.

sreten 11th October 2012 01:56 AM


They are unusual, being female and you wont find any mains leads with male
connectors. Change them to the usual male sockets for the usual female plugs.

rgds, sreten.

Typical mains lead :

Typical mains socket :

hochopeper 11th October 2012 02:10 AM

They are unusual for a reason, they are power output. Having live exposed terminals is a bad idea.

The OP wants a IEC female - IEC male lead, they are commonly used for power distribution from UPS (uninterrupted power supply). An alternative is something like this

sreten 11th October 2012 02:21 AM


Originally Posted by hochopeper (
They are unusual for a reason, they are power output.
Having live exposed terminals is a bad idea.


You are quite right, and that makes perfect sense.

The lead and input socket I showed are exactly that,
mains input, whilst here its mains output, so your
going to need a unusual mains lead, male to female.

rgds, sreten.

My advice to change them is dreadful .... muppet ....

rize 11th October 2012 05:23 AM

Did a little more research to find out the receptacles are IEC 60320-2-2 Class I Power Components - plug connector Sheet E to be exact.
Just one Sheet E connector is $13 plus S&H for one plug at Amazon !
I'm definitely inclined to change the Sheet F outlets to standard female outlets since they are power output. A cheaper alternative is AC Female Outlet~PC Male Power Adapter Cable/Cord/Wire IEC320 C13/C14.

No wonder the transformer was priced rather low on eBay. I overlooked the fact that outlets will not work with standard AC connector plugs. Fortunately it came with it's own power chord, standard 3-prong plug. Aside from the receptacle issue, it's appears to be well-made, included documentation showing the circuit.
Thank you for your comments.

hochopeper 11th October 2012 05:57 AM

DO NOT change the outlet connectors on the device. This will have exposed live parts and be a SERIOUS health hazard.

DO purchase the correct leads - IEC 320 Sheet E to IEC C13 Power Cord or the IEC -> 3 pin plug adapter for your country (Aus equivalent linked in my previous post).

kevinkr 11th October 2012 06:08 AM

I use a couple of these transformers in my system, the proper plugs are readily available on eBay for short money as are short pigtails with standard NEMA 15A sockets on one end and IEC with male pins on the other.

No need to modify the transformer, and in fact since all of the components in my system use IEC connectors I am contemplating changing the plugs on the power cables to use the IEC with male pins.

I've got a 600VA and a 1kVA made by Toroid Corp of Maryland, the maker of your unit. The company is very much still in business, in fact we have a bunch of these at work. (I work in medical electronics.)

Note that the output is floating and interestingly I found that the overall hum level in my system decreased very slightly.

DF96 11th October 2012 06:27 PM

Those IEC power input/output sockets are perfectly normal and standard in Europe. The cables are widely available over here.

leadbelly 11th October 2012 07:20 PM

Sourcing that cable connector should be pretty easy at a computer recycler. It used to be common for the computer CRT monitor to be plugged into the back of the computer PS. I had at least 1 old PC monitor and 1 old Mac monitor that that had the male IEC connector for power.

Davey 11th October 2012 07:37 PM

Plenty of suitable cords available at Digikey, Mouser, etc. A typical example:

AK500-OE-11-1-R Assmann WSW Components | AE9911-ND | DigiKey


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