I have a question pertaining to the use of flexible cords in an industrial environment. There is an industrial dry pump that is permanently anchored to the floor that is powered by a flexible cord connected to a disconnect located near the equipment. looking at the power connector on the back of the dry pump, it doesnt look like it can accept flexible conduit to the connector.
So my question is. I know the NEC states that any equipment that is permanently installed should have permanent wiring (i.e. flex conduit or hard conduit), but what about equipment that only accepts flexible cords and is permanently anchored to the floor?
Any thoughts on this would be greatly appreciated. thanks, Eleazar Martinez
would the installation still be compliant if manufacture states the power connection on the back of the unit is meant for flex cord?
Im sure if the manufacture wanted they could supply the unit with a power connector that was compatible with hard wiring the unit. would it be better to get a hold of the manufacture and have them supply a different power cord or leave as the original installation?
I think it really gets back to the listing. If they had a corded model evaluated, you can put an equivalent U/L listed cord set on it. You see this with things like dishwashers and disposals. You can order the identical model hard wired or corded and the instructions will address both. When my wife was building houses, all of these things were corded and dropped right before the house closed so they wouldn't walk away.
Speaking as someone with direct access to the inner workings of the pump standard ... now, consider the following comments to be absolute Gospel from the ultimate authority- if presented in a casual manner:
The pump standard has all manner of provisions regarding pumps and the use of cords with them. There has been some 'loosening' of the rules in the past few years as various matters have been clarified.
Simply put: Lighten up, people! Just about any pump can be fitted with any cord, of any (reasonable) length, and not violate the listing & labeling. Even rigging a cord to a pump that is "usually" hard-wired does NOT constitute a violation of the listing.
The connection boxes are evaluated using the biggest connectors that will fit. Various pump makers have provided plenty of substantiation for the use of cords in various situations. There's a whole industry (IE: Meltric) built on the idea of using cords.
True, the details CAN matter. For example, it is imagined that a pump in a wash-down situation would be connected using wet-location fittings. It's the responsibility of the AHJ, and not the testing lab, to judge whether a particular fitting and cord are acceptable.
Yes, there has been a lot of parsing with regards to dishwashers and disposals. Those are different appliances, and are evaluated under a different standard than the one for electrically powered water pumps. Different standards, different committees, different rules. (Witness the recent increase in the allowed length of cord on a dishwasher!).
The OP asked about pumps in an industrial environment. This introduces several "special exemptions" into the question. These include vibration isolation, ease of maintenance, and a 'supervised' maintenance program with 'qualified' people.
Now... that said ... there are a heck of a lot of pumps that are not 'listed' by anyone. The pump industry has a century-long history of producing all manner of top-quality, perfectly safe pumps without the blessings of any testing lab. You can't violate the listing of something that's not listed!
(6) Connection of utilization equipment to facilitate frequent interchange (7) Prevention of the transmission of noise or vibration (8) Appliances where the fastening means and mechanical connections are specifically designed to permit ready removal for maintenance and repair, and the appliance is intended or identified for flexible cord connection
You can usually find enough wiggle room in one of these to connect just about anything with a cord.
On a pump, one thing that might guide me decision was if the plumbing side was installed in a way that "facilitate(d) frequent interchange" like a hose coupling or unions. If they are cutting pipes, they can disconnect some wiring.