European machine in US

[pfalcon]

A machine showed up in our shop that was bought by an ME from a french company.

We have 480V 3-ph; the machine has european cord and plug for 230V 1-ph. Internal conductors (serviceable) are labeled L* and N* with dual-pole fuse blocks where the L* have fuses and the N* have trapped shorting bars. So to change a fuse on an L conductor you break both L and N.

I'm thinking I have to refit this machine with dual-pole blocks both fused and leave N floating or replace with single-pole blocks for L and terminal strips for N and ground N.

I'm contacting the home company to see if floating/grounding of N is important. Third-party conversations gave rumor they expected us to just replace the european plug with a 240V appliance plug.

Any advice?

 

[Besoeker]

A machine showed up in our shop that was bought by an ME from a french company.

We have 480V 3-ph; the machine has european cord and plug for 230V 1-ph. Internal conductors (serviceable) are labeled L* and N* with dual-pole fuse blocks where the L* have fuses and the N* have trapped shorting bars. So to change a fuse on an L conductor you break both L and N.

I'm thinking I have to refit this machine with dual-pole blocks both fused and leave N floating or replace with single-pole blocks for L and terminal strips for N and ground N.

I'm contacting the home company to see if floating/grounding of N is important. Third-party conversations gave rumor they expected us to just replace the european plug with a 240V appliance plug.

Any advice?

The circuit will work whether or not the neutral is grounded but the customary arrangement and in EU land is for the neutral to be grounded and often at the supply transformer. Normally the live is fused and the neutral has a solid neutral link. My preference would be to stick with the grounded neutral arrangement. If the neutral is not grounded and you have a live to ground fault there would be no path for fault current and the kit would sit there with the neutral at 230V wrt ground. And I don't think that is desirable.

 

[james_mcquade]

be sure that the system is not entirely 230 volts single phase. the US uses 110 volts as the standard household / control voltage while
they have no 110 volts in the UK for example - its 230 volts.
also be aware that their typical frequency is 50 hz not 60. some machines will have the 50/60 hz ratings on coils.
but even then, its been my experience that you will end up replacing all coils within 6-9 months, they burn up.

do your research on how the machine is wired. take time to cross the t's and dot the i's.
it will take longer, but it may save a lot of heartache in the long run.

regards,
james

 

[fmtjfw]

A machine showed up in our shop that was bought by an ME from a french company.

We have 480V 3-ph; the machine has european cord and plug for 230V 1-ph. Internal conductors (serviceable) are labeled L* and N* with dual-pole fuse blocks where the L* have fuses and the N* have trapped shorting bars. So to change a fuse on an L conductor you break both L and N.

I'm thinking I have to refit this machine with dual-pole blocks both fused and leave N floating or replace with single-pole blocks for L and terminal strips for N and ground N.

I'm contacting the home company to see if floating/grounding of N is important. Third-party conversations gave rumor they expected us to just replace the european plug with a 240V appliance plug.

Any advice?

Yea, don't worry about it. N is neutral not grounding. Grounding is going to be marked with standard symbol or perhaps E. Neutral is probably Blue. Grounding is Green with a Yellow stripe. Single phase power hot is normally brown.

NEC allows the simultaneous opening all the hot and neutral conductors. In wiring to gas pumps, for instance, such a setup is required.

Is the setup as follows: a disconnect/door lock that must be operated to open the incoming power and unlock the door to the fuse area? If not the control area is probably finger safe. How many fuse blocks are there?

I usually replace the european (most likely a 2-prong Shuko with grounding on the sides or a hole for a grounding pin if it is the French version) with a standard NEMA 6-15P 250v/15a grounding plug. Just follow the colors as above.

The French receptacles (with a grounding pin sticking OUT OF THE RECPTACLE) are polarized. The German ones (even though they mark neutral with blue) are not polarized. So connecting N to a hot is not a problem. Although it is very unlikely you should verify that N is not used as the grounding conductor.

I've got 250v receptacles in the kitchen for waffle irons and in the sewing room for clothes iron and sewing machine. Before my German dorm sized refrig died (after about 30 years on 60HZ) I used an isolation transformer as an autotransfomer to power it from 125v.

 

[fmtjfw]

be sure that the system is not entirely 230 volts single phase. the US uses 110 volts as the standard household / control voltage while
they have no 110 volts in the UK for example - its 230 volts.
also be aware that their typical frequency is 50 hz not 60. some machines will have the 50/60 hz ratings on coils.
but even then, its been my experience that you will end up replacing all coils within 6-9 months, they burn up.

do your research on how the machine is wired. take time to cross the t's and dot the i's.
it will take longer, but it may save a lot of heartache in the long run.

regards,
james

Interesting about coil failure... Is this contactor or relay coils? So do they chatter or hum before failure? I would think if they fully pull in then they would be subjected to lower currents since 60HZ impedance should be higher than 50HZ?

 

[Besoeker]

be sure that the system is not entirely 230 volts single phase. the US uses 110 volts as the standard household / control voltage while
they have no 110 volts in the UK for example - its 230 volts.
also be aware that their typical frequency is 50 hz not 60. some machines will have the 50/60 hz ratings on coils.
but even then, its been my experience that you will end up replacing all coils within 6-9 months, they burn up.

do your research on how the machine is wired. take time to cross the t's and dot the i's.
it will take longer, but it may save a lot of heartache in the long run.

regards,
james

Good point about the 50 Hz.
Coils will draw less current at 60Hz. The issue can be that relays and contactors might not pull in correctly.

 

[pfalcon]

The circuit will work whether or not the neutral is grounded but the customary arrangement and in EU land is for the neutral to be grounded and often at the supply transformer. Normally the live is fused and the neutral has a solid neutral link. My preference would be to stick with the grounded neutral arrangement. If the neutral is not grounded and you have a live to ground fault there would be no path for fault current and the kit would sit there with the neutral at 230V wrt ground. And I don't think that is desirable.

LNG circuit. Hot, grounded return, ground.

... some machines will have the 50/60 hz ratings on coils.
but even then, its been my experience that you will end up replacing all coils within 6-9 months, they burn up. ...

Rated 50/60.

... NEC allows the simultaneous opening all the hot and neutral conductors. In wiring to gas pumps, for instance, such a setup is required.

Is the setup as follows: a disconnect/door lock that must be operated to open the incoming power and unlock the door to the fuse area? If not the control area is probably finger safe. How many fuse blocks are there?

I usually replace the european (most likely a 2-prong Shuko with grounding on the sides or a hole for a grounding pin if it is the French version) with a standard NEMA 6-15P 250v/15a grounding plug. Just follow the colors as above.

The French receptacles (with a grounding pin sticking OUT OF THE RECPTACLE) are polarized. ...

Thoroughly a French machine with French receptacle. Everything in the panel is finger-safe.
What's the code section that allows opening the grounded neutral conductor?

 

[fmtjfw]

LNG circuit. Hot, grounded return, ground.


Rated 50/60.


Thoroughly a French machine with French receptacle. Everything in the panel is finger-safe.
What's the code section that allows opening the grounded neutral conductor?

404.2(B)
Exception: A switch or circuit breaker shall be permitted
to disconnect a grounded circuit conductor where all circuit
conductors are disconnected simultaneously, or where
the device is arranged so that the grounded conductor cannot
be disconnected until all the ungrounded conductors of
the circuit have been disconnected.

 

[pfalcon]

404.2(B)
Exception: A switch or circuit breaker shall be permitted
to disconnect a grounded circuit conductor where all circuit
conductors are disconnected simultaneously, or where
the device is arranged so that the grounded conductor cannot
be disconnected until all the ungrounded conductors of
the circuit have been disconnected.

Thanks for the reference. I don't think it applies in this case. These are fuse blocks not switches.

 

[fmtjfw]

You are over thinking this too much

You are over thinking this too much

Thanks for the reference. I don't think it applies in this case. These are fuse blocks not switches.

Sure they are a switch. A switch is something that opens a circuit. They open a circuit. Go outside and stare at a transformer mounted on a pole. Connecting it to the hot conductor 99% of the time is a fused disconnect that is functionally equivalent to what you describe: a device, containing a fuse that can be opened for replacement of the fuse and which opens the circuit when you do that.

The part I quoted specifically mentioned Circuit Breakers, which are a switch and OCPD combined. This is what you describe: a device that is an OCPD and opens the circuit. Their purpose is to open the circuit so you can replace the fuse only when it is deenergized.

 

[pfalcon]

Sure they are a switch. A switch is something that opens a circuit. They open a circuit. Go outside and stare at a transformer mounted on a pole. Connecting it to the hot conductor 99% of the time is a fused disconnect that is functionally equivalent to what you describe: a device, containing a fuse that can be opened for replacement of the fuse and which opens the circuit when you do that.

The part I quoted specifically mentioned Circuit Breakers, which are a switch and OCPD combined. This is what you describe: a device that is an OCPD and opens the circuit. Their purpose is to open the circuit so you can replace the fuse only when it is deenergized.

The provisions of this article shall apply to all switches, switching devices, and circuit breakers where used as switches.

Which implies there are circuit breakers that aren't used as switches. I still don't believe 404 applies.

No overcurrent device shall be connected in series with any conductor that is intentionally grounded, unless one of the following two conditions is met: (1) The overcurrent device opens all conductors of the circuit, including the grounded conductor, and is designed so that no pole can operate independently. (2) Where required by 430.36 or 430.37 for motor overload protection.

I think this is what I'm looking for. Some confirmation would be nice.


Thanks,

 

[pfalcon]

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