What diversity factor to be applied to a three phase food holding unit?

[Ronnie-p]

Hi there
currently doing some diversity calcs for college work and had a query about what diversity factor to apply to a 16A 3 phase commercial food holding unit.
I'm thinking that this equipment will be only used in the day time(breakfast, Lunch and Tea (what we call the evening meal- dinner or supper or whatever you southerners call it) so it won't be in use at night and only in the day and for this reason I think a 70 % factor would be acceptable, although the on site guide says that the rated current should be taken (table A1)

 

[davesparks]

I'm thinking that this equipment will be only used in the day time(breakfast, Lunch and Tea (what we call the evening meal- dinner or supper or whatever you southerners call it) so it won't be in use at night and only in the day and for this reason I think a 70 % factor would be acceptable,

The times of day that it is used don't affect the diversity factor, diversity is used to assess the likely current demand of a load, or group of loads when in use.

The time of day that it is used won't affect the diversity of the single load, but might come in to play if you are assessing the demand of a whole installation.

although the on site guide says that the rated current should be taken (table A1)

I agree, for a single appliance, with no further details about how it works, I would take the full rated current with no diversity applied.

If you had a larger number of these appliances then you would start to apply diversity as the cycling of the thermostats in them woukd mean that they will never all be on at once.

 

[pc1966]

Commercial kitchen stuff is not normally assumed to have any usable diversity, as the chefs tend to bang everything on at once to begin with as they get stuff ready for all of the cooking in parallel.

Domestic cookers hardly ever see that sort of use.

 

[Ronnie-p]

The times of day that it is used don't affect the diversity factor, diversity is used to assess the likely current demand of a load, or group of loads when in use.

The time of day that it is used won't affect the diversity of the single load, but might come in to play if you are assessing the demand of a whole installation.


I agree, for a single appliance, with no further details about how it works, I would take the full rated current with no diversity applied.

If you had a larger number of these appliances then you would start to apply diversity as the cycling of the thermostats in them woukd mean that they will never all be on at once.

ye think I was probably overthinking it because with the lights when diversity is applied is because lights wont be on all the time so I was thinking the same logic might be applied here but I did see that the on site guide said no diversity should be applied to stationary equipment - I just had the trail of thought about it not being on in the night and whether diversity then applies there. But when I think of it now dishwashers will only be one once, maybe twice a day and I've done no diversity for that as it can be classed as a thermostatically controlled water heater(OSG says no diversity for these) as well as being stationary equipment
But thanks for your input and I will change it to no diversity applied