bonding coldrooms

[Steve]

Picture the situation. A chiller coldroom installed onto the wooden floor, with no insulated base (there may be insulation underneath the floor). A fan cooling unit hung from the ceiling inside (Searle twin fan) with power and pipework entering from above. Copper drainage pipe, well insulated (more on this later)

Next door is a freezer coldroom, smaller, but with the same Searle twin fan cooler, same installation method for cable and pipework. Metal plated insulated floor panels, floor raised up 4 inches.

The drainage pipe is also copper, however being in the freezer it has heat tape wrapped round it. The pipe from the freezer runs into the fridge along the back walls, through the single dividing wall. It joins to the fridge drain pipe, then goes off through the back wall, and through a steel framed stud wall. On the other side (still indoors) the copper pipe empties into a plastic one.

Now, is there any need to bond the copper pipe to the main body of the cooler unit in either case?

If so, why? Where is any potential going to come from in this scenario?

 

[Lectrician]

None at all.

 

[electronicsuk]

I'm not so sure - a failure of basic insulation on the heating tape could cause the copper drain pipework to become live under fault conditions, therefore it would seem to make sense to bond it, on the basis of it being an exposed conductive part.

 

[RF Lighting]

Surely that would be earthing, rather than bonding though

 

[Steve]

OK. They guys who fitted the units bonded the drain pipes to the body of both the coolers with great long curls of G/Y.

Freezer

Fridge

Just visible in the first pic is the outlet for the heater tape behind the cooler. Not visible in either is the bonding which has been neatly fitted behind the pipework.

Should have mentioned the metal shelves i guess.

I suppose this was a belts and braces install. They certainly took no chances, theres three large compressors on the roof, each draw 17 amps per phase and wieghs over 100kg. The whole shop (28.2metres of open front fridges and the chiller coldroom, as well as 5 airconditioners) could run on just one, the other two are for redundancy in case one breaks.

 

[ColJack]

are the walls plastic SIPs or plastic coated steel SIPs?

if they are plastic, and you're on an wooden floor then there is no earth potential in there besides that introduced by the chiller units..

 

[Lectrician]

x

 

[ColJack]

x

very helpfull and most informative of your mental state... thank you for you input...

 

[mdbalson]

x

very helpfull and most informative of your mental state... thank you for you input...

 

[mdbalson]

OK. They guys who fitted the units bonded the drain pipes to the body of both the coolers with great long curls of G/Y.

I have seen the drain pipes bonded to the evaporator body before at some of the sites I have worked at.

I suppose this was a belts and braces install. They certainly took no chances, theres three large compressors on the roof, each draw 17 amps per phase and wieghs over 100kg. The whole shop (28.2metres of open front fridges and the chiller coldroom, as well as 5 airconditioners) could run on just one, the other two are for redundancy in case one breaks.

One of the condensers would be just for the airconditioning, due to the fact that in the winter you would want the air con to heat the store & the not chill it.

 

[ColJack]

17A per phase... pftttt.. tidlers..

define compressor?

you get single scroll compressors, or you get them in banks for staged demand..

we built units that had 3 tripple compressors, and that just did the air can