Alwayslearningelec
Senior Member
- Location
- NJ
- Occupation
- Estimator
Is the difference between the two just the increased support with double expansion? Are these the preferred ones to use for trapeze racks?
Expansion Vs. Double Expansion
- Thread starter Alwayslearningelec
- Start date
- Location
- New Jersey
- Occupation
- Journeyman Electrician (retired)
If you're hanging racks from solid concrete I would not use a double expansion shield. There are better anchors that are easier to install in concrete than double expansion shields. Double expansion shields require you to drill very large holes relative to the rated size of the shield which can greatly increase your chances of hitting rebar and having to re-drill the hole.
- Location
- Illinois
- Occupation
- retired electrician
What material is the anchor going into? It is my understanding that you use the double expansion anchors for softer materials, and the single expansion for harder materials like poured concrete.
- Location
- New Jersey
- Occupation
- Journeyman Electrician (retired)
I agree. We would reserve the use of double expansion shields for something like cinder fill concrete.
Alwayslearningelec
Senior Member
- Location
- NJ
- Occupation
- Estimator
Concrete deck/slab. What would you use and would it change if it were a small/lightweight racks compared to a very large/heavy rack?
- Location
- Illinois
- Occupation
- retired electrician
Single expansion for me.
Alwayslearningelec
Senior Member
- Location
- NJ
- Occupation
- Estimator
it's amazing this little think can hold 1/2" rod with possible A LOT of weight?
- Location
- New Jersey
- Occupation
- Journeyman Electrician (retired)
That particular anchor is designed for shallow mounting like in hollow block.
- Location
- Illinois
- Occupation
- retired electrician
I would be using a drop-in type anchor in poured concrete.
SceneryDriver
Senior Member
- Location
- NJ
- Occupation
- Electrical and Automation Designer
Hilti drop-in anchors are wonderful. Be sure to get the pin setting tool - don't try to set them with a center punch or a screwdriver. Also, pay close attention to the load ratings, which are based partly on the PSI of the concrete they're going into. If in doubt, consult a structural engineer. Hilti also has knowledgeable application engineers, but nothing substitutes for a stamped letter/detail drawing showing anchoring especially when suspending significant loads. Look at what happened in the Boston Big Dig to see what happens when overhead suspension plans are ignored.
SceneryDriver