208 range on 240 delta

[AC\DC]

Howdy owner bought a range with 208/120 3 phase
Her service is 240/120 highleg 3 phase
Her stove has no neutral.
I saw a post were I could use 2 buck boost open to get it down to 208.
Will elements blow up if connected to 240-120 over 208/120?
I am not going to connect just wondering

 

[tom baker]

If the label only shows 208 then it would be a violation to use on 240. With motors it’s an issue due to overvoltage causes excessive current. Stoves would operate hotter.
I have seen many many cases of getting a 208 v something to use in 240 and vice versa.

 

[drcampbell]

The heating elements will operate at a higher wattage and temperature than they're designed for. The temperature controls will switch a higher current than they're designed for.

I will most likely "work", in the most superficial sense of the word.
But it will be troublesome, prone to frequent failures, prone to nuisance trips of the circuit breaker, and probably be a fire hazard.

As cheap & simple as it is to replace heating elements, why not do that?

No white wire? Don't stovetop heating elements usually operate on 120 volts?

 

[AC\DC]

I can see we’re the elements would cause a problem if there limit is 208 volts.
If she changes the elements at 600 a wack she got around 4k
Plus the nameplate says 208 so would still be in violation.
There is no 120 volt lights or timers on this unit
. so I think either i buck it or she gets a new stove.

 

[readydave8]

Don't stovetop heating elements usually operate on 120 volts?

commercial range if it is 3 phase

 

[LarryFine]

I saw a post were I could use 2 buck boost open to get it down to 208.

You can do it with one if it's 1ph.

 

[AC\DC]

No it’s 3phase stove. she looking into getting the correct stove. Just 6 months out

 

[gene6]

I have installed several 208Y ranges on 240D. They don't actually bake hotter, they pull more current. In my case the manufacturer was most helpful (Vulcan). You need to check the ampacity/max wattage of the cal rod or whatever the elements are.
The most I ever had to do was a little wiring reconfiguration and replace 120V indicator and interior lights with 240V ones.

 

[petersonra]

Howdy owner bought a range with 208/120 3 phase
Her service is 240/120 highleg 3 phase
Her stove has no neutral.
I saw a post were I could use 2 buck boost open to get it down to 208.
Will elements blow up if connected to 240-120 over 208/120?
I am not going to connect just wondering

your best bet is to buy a 3 phase 240-208 transformer.

 

[kwired]

No it’s 3phase stove. she looking into getting the correct stove. Just 6 months out

How "hot" is your 240 volt supply? If it operates at lower end of what is acceptable it may not be too significantly higher than the upper end of what is acceptable for a 208 supply. In that case maybe just use as is if only going to be six months, that may also depend on intended usage.

The real key to life of the elements is how hot will they get? As long as you don't let them sit there with "load" on them to absorb heat they won't get as hot. That kind of works for surface elements of a range but not so much for an oven element that doesn't have it's cook items in contact with it.

 

[synchro]

You could use a 240/208V 3-phase autotransformer that'll be about half the cost and one third the weight of a delta-wye:

HAMMOND Y030CECF3L0U AUTO 30KVA 240-216-208V CU 3R NEUTRAL 60HZ | Gordon Electric Supply, Inc.

HAMMOND Y030CECF3L0U AUTO, 30KVA, 240-216-208V, CU, 3R, NEUTRAL, 60HZ

www.gordonelectricsupply.com

210.9 Exception No. 1 allows branch circuits to be derived from autotransformers without a connection to a grounded conductor when transforming between 240V and 208V.

 

[petersonra]

You could use a 240/208V 3-phase autotransformer that'll be about half the cost and one third the weight of a delta-wye:

HAMMOND Y030CECF3L0U AUTO 30KVA 240-216-208V CU 3R NEUTRAL 60HZ | Gordon Electric Supply, Inc.

HAMMOND Y030CECF3L0U AUTO, 30KVA, 240-216-208V, CU, 3R, NEUTRAL, 60HZ

www.gordonelectricsupply.com

210.9 Exception No. 1 allows branch circuits to be derived from autotransformers without a connection to a grounded conductor when transforming between 240V and 208V.

We do not know if the stove needs a neutral or not. If it does, the source is not going to have a neutral in the right spot, and there is no amount of jury rigging is going to fix it. Best to spend the money and do it right once.

 

[LarryFine]

The OP said it's 208/120, suggesting the neutral is needed.

I recommend getting an appliance that suits the supply.

 

[petersonra]

The OP said it's 208/120, suggesting the neutral is needed.

I recommend getting an appliance that suits the supply.

Or adjust the supply so it matches the appliance that was purchased.

But trying to jury rig something to save a few bucks is nuts. It is just about guaranteed to screw it up somewhere down the road.

 

[synchro]

In post #1 the OP said the stove has no neutral.
But if it needs a neutral, the Hammond autotransformer I mentioned above has an option for a connection to the center tap of the wye. The OP would have to check whether its availlability meets his needs.

Do I need to connect the neutral and ground my HPS three-phase autotransformer?

$name

americas.hammondpowersolutions.com

It would certainly be better if the appliance matches the available supply as Larry said. A transformer is going to continually draw current for excitation of the core whether it has a load or not. A 240/208V autotransformer will have significantly less excitation current than a delta-wye. Roughly speaking, it would go up proportionally with the weight of the transformer core.

 

[synchro]

I see in post #1 that the supply is a high leg delta. And so connecting a neutral tap on a 3-phase autotransformer would be a bad idea in this case.

 

[AC\DC]

No neutral is required. It’s stated in the first post. Have not read the post past the auto transformers suggested

 

[synchro]

No neutral is required. It’s stated in the first post. Have not read the post past the auto transformers suggested

It would still be worthwhile to consult the range manufacturer to verify that it's OK to have the three line-to-ground voltages not be the same.
In VFD's that can be an issue with high-leg deltas because of internal surge suppressors that are from line to ground.

 

[drcampbell]

... As long as you don't let them sit there with "load" on them to absorb heat they won't get as hot. That kind of works for surface elements of a range but not so much for an oven element that doesn't have it's cook items in contact with it.

You have that backwards. Putting a thermal "load" on a heating element -- such as a pot of cool water in contact with a stovetop element -- will reduce its average temperature. But it won't reduce its peak temperature, which is going to be the point of failure.

It would still be worthwhile to consult the range manufacturer to verify that it's OK to have the three line-to-ground voltages not be the same.
In VFD's that can be an issue with high-leg deltas because of internal surge suppressors that are from line to ground.

They're also likely to interpret a significant imbalance in the phase-to-ground voltages as a phase loss and refuse to start.

 

[AC\DC]

They said it would not effect it.
Thanks I forgot to ask that