Hatco Model GRA-96

[ectofix]

A few things –

 

VOLTAGE:  You didn’t specify what voltage you’re running.  You said you’d replaced the elements.  Did you put the right ones in?  If you installed 208v elements, but your voltage is much higher (above 220v), the elements will run hotter.  So maybe 240v elements would be more suitable.

 

CONTROLS:  For controls, it could be just a toggle switch or it could be an infinite switch.  The toggle switch will have the elements running full bore all of the time, while the infinite control can adjust heat output.  So the electrical load varies.

Either switch might be mounted inside of the fixture…or in a remote box.  I’ve gone and put a remote box in for some heat lamps simply because circumstances have demonstrated that the switch tends to live a shorter life when exposed to the very that the fixture generates.

 

WIRING:  What kind did you use?  Did you use PTFE wiring?  It’s become popular in the last ten years.  It’s cheaper and claims to be high-temp, but it’s only good to nearly 400°.  TGGT wire is better due to having a bit higher temp rating of nearly 500°.  However, the best high-temp wire is MGT – which withstands around 1000°.  I don’t know which of the latter two that Hatco uses, since they’re both encased in fiberglass sheathing and look similar. PTFE isn’t.  Hatco doesn’t use the basic PTFE version of high-temp wire in their fixtures.

 

CONNECTIONS:  The fewer, the better.  Avoid segmenting a circuit with a chain of wire nuts if you can. A constant resistive load such as a heat lamp takes a toll on bad connections.  They’re weak point in the circuit and will get hot (due to resistance) if not done correctly.

A bad connection is perpetual.  A little resistance at a poor connection causes heat.  Heat causes more resistance…then resistance causes even more heat – and so forth.  Then the connection eventually melts wire insulation and damages components before the actual connection (or wire…or component) ultimately gives out altogether.

Crimp connections are typical for the wire terminals, but the connection lasts longer if the crimp to the wire is followed up with solder.  That’s not often done though.  I’ve rarely done it myself..but I have done it when the occasion seemed to need it.

So if it’s just a crimp you’re going with, make sure the wire strands are clean (with no signs of oxidation or discolored from prior overheating) and connections are tight.  When making a repair, cut the wire back to find clean strands.  Use fresh, new HIGH-TEMP terminals.  If you cut the wire back, stripped it and it doesn’t appear NEW…no matter how far you cut it back, replace the wire entirely.

Good, clean connections are equally as important for the wire terminal’s lug connections (with a screw) to the elements or toggle switch…and the same for the push connectors to an infinite control.

Good, clean solid, TIGHT connections.

 

INSULATION:  Is the wiring routed within the fixture at the furthest possible run where it’s well away from the element?  To rewire a heat lamp, it’s best to dismount it, turn upside-down, remove EVERYTHING …including the insulation …and run the wires between the outer casing and insulation.  In some cases, this can be a major undertaking.  But coming back and doing it correctly a second or third time isn’t what I like to be doing.

Also…at each end of the fixture there are metal guards, wire shields and…on the switch-end for the switch and power cord, a block of insulation.  Make sure all of that is in place and tightly secured.

 

Hope this helps…

[fixbear]

Like to add that the wire should be siver coated and the crimp terminals need to be made with a good crimper like a Pallidin.

[ectofix]

Pallidin?  All these years and never heard of them.  That’s good info.  Thanks!

 

Like Knipex pliers.  I worked for years with other brands, then got some of those.  I’ll never go back.

[fixbear]

There are several tools out there. The good ones are pricey, but worth the cost. They all have changable dies and must go to complete crimp before releasing. Handles are $60 to $80 and the dies are $25 or so.I have 6 different dies and 2 handles for all the different terminals I’ve had to do over the years. Bigger stuff I use a Square D hydraulic crimper.that will go from 8 up to 500 MCM.

[kendog]

The wrong voltage scenario is a common problem. As are crimps. Also verify you didn’t install the GRAH elements which are higher output. If that is good, check the wire gauge versus total amp draw. There are online calculators and even apps that will recommend wire gauge for power.

[gregct]

Definitely need to make sure the terminals are nickel plated high temp rated terminals and not ‘everyday general use’ with nylon insulation around the crimp and that all the connection points are thoroughly cleaned with emory cloth or another suitable abrasive. 

 

https://www.delcity.net/store/High-Temperature-Ring-Terminals/p_806250.h_806253.r_IF1003?mkwid=s&crid=38094426869&mp_kw=&mp_mt=&gclid=CjwKCAjwy7vlBRACEiwAZvdx9pLGt54G9uouRg2pJcWWLbUGPlZpILTC1KbxT6hoLGoyvI2nBQ7waBoCqzMQAvD_BwE

 

Is what the terminals should look like, a general use terminal will probably last 8 hrs or less at the temps expected. We normally take it to the next level, and pull the next wire gauge up sized high temp wire in the first time one burns up, seems to help although if originally wired with 12 ga, its a little tough to pull in 10’s but the heat reduction even if minimal does make a difference.